Five people have died after a helicopter crashed in mountainous Victorian terrain, in one of the state's worst civil aviation disasters in decades.

Police confirmed four passengers and a pilot died at the scene after the aircraft crashed at Mount Disappointment about 9.30am on Thursday.

The five people on board included four men and one woman aged from 32 to 73. Three were from Victoria and two from NSW.

Their remains were found after ground crews battled steep terrain and dense forest to reach the wreckage of the helicopter near Blair's Hut about 3.45pm. It was earlier spotted by the police air wing.

"The helicopter's been destroyed and unfortunately there were no survivors," acting inspector Josh Langelaan told reporters on Thursday night.

"It was a confronting scene. Until we actually located the remains on the five people, we remained hopeful that we might find somebody alive."

The helicopter was one of two that left the Melbourne CBD in the morning, flying in convoy over Mt Disappointment on its way to Ulupna near the Victorian/NSW border.

The passengers were travelling to the border as part of a business trip, police said. There were no details shared on their relationship.

Mr Langelaan said there was low cloud over Mt Disappointment when one of the helicopter ran into trouble.

"One helicopter came through the cloud found the other one was missing and police were notified," he said.

The second helicopter, also believed to be carrying four passengers and a pilot, later landed at Moorabbin Airport in Melbourne's southeast.

The operator of the helicopters, Microflite, said the company would co-operate with an investigation into the cause of the crash.

"I extend my deepest condolences to all affected by this incident who we are supporting through this very difficult time," Microflite executive general manager Rod Higgins said in a statement.

It is believed to be Victoria's deadliest aviation disaster since February 2017, when five people were killed after a charter plane crashed into Melbourne's Essendon DFO shopping centre.

At the time, Premier Daniel Andrews said it was the state's worst civil aviation accident for 30 years.

The Australian Transport Safety Bureau will take over the investigation on Friday and is expected to remain on site for several days.

Bulldozers and an excavator have been called in to clear a path to the crash site.

Mt Disappointment was the scene of a major search operation in 2020 for autistic Victorian teenager William Callaghan, who was found alive after spending two nights missing in the bush.

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Chris Rock has received several standing ovations before he told one joke at his first comedy show since Will Smith slapped him in the face on stage at the Oscars.

Rock only briefly addressed the slap to the sold out crowd in Boston on Wednesday night, saying he was "still kind of processing what happened".

"Other than the weird thing, life is pretty good," Rock said midway through his first of two sets.

The performances came just three days after Smith smacked the comedian for making a joke about his wife, Jada Pinkett Smith, while presenting an Academy Award.

Rock didn't mention Smith or Pinkett Smith by name at his show in Boston. Wearing all white, he seemed to be almost embarrassed by the multiple ovations he received.

As the applause carried on for minutes -- with fans yelling "I love you, Chris!" -- the comedian appeared to be getting emotional, a guest seated near the stage told The Associated Press.

"How was your weekend?" Rock joked before getting into his set.

Ticket prices skyrocketed after Smith took to the awards stage and slapped Rock on live TV, but the comedian made clear he wasn't going to talk at length about it on Wednesday.

"If you came to hear that, I'm not ... I had like a whole show I wrote before this weekend," Rock said.

He spent much of the night skewering celebrities and politicians. Among them were the Duchess of Sussex, the Kardashians, as well as President Joe Biden, Hillary Clinton and former president Donald Trump.

Outside the venue, a fan showed off a T-shirt featuring the "G.I. Jane" logo and Pinkett Smith's face. Another had a shirt he made that showed Smith's face and displayed a crude joke about the couple's relationship.

At least one person yelled during the show that Rock should sue Smith.

Rock's joke at the Oscars was about Jada Pinkett Smith's buzzed haircut: "Jada, I love you. 'G.I. Jane 2,' can't wait to see it," Rock said, comparing Pinkett Smith to Demi Moore's "G.I. Jane" character, who had a buzz cut in the 1997 film.

Smith promptly stood up from his seat at the front of the venue and took to the stage, slapping Rock across the face before sitting back down and yelling at Rock to keep his wife's name out of his mouth.

Pinkett Smith has spoken publicly about her diagnosis of alopecia, which can cause baldness.

Within an hour, Smith won best actor, receiving a standing ovation. During his five-minute acceptance speech, Smith talked about defending his family and apologised to the academy.

A day later, Smith issued an apology to the comedian, to the academy and to viewers at home, saying he was "out of line" and that his actions are "not indicative of the man I want to be."

The Academy of Motion Pictures Arts and Sciences condemned Smith striking Rock. Its board of governors met on Wednesday to initiate disciplinary proceedings against Smith for violations of the group's standards of conduct.

The academy said it had asked Smith to leave the ceremony after hitting Rock, but he refused to do so.

© AP 2022

Australia will provide a further $25 million of defensive military equipment for Ukraine to help the country's military forces against Russia's invasion.

Scott Morrison announced the package - which includes tactical decoys, unmanned aerial and ground systems, rations and medical supplies - ahead of Ukrainian President Volodymyr Zelenskiy addressing parliament.

The prime minister said the assistance came at the request of the president.

"The Australian government will continue to identify opportunities for further military assistance where it is able to provide a required capability to the Ukraine Armed Forces expeditiously," he said.

The measures were announced alongside an additional 35 per cent tariff for all imports coming from Russia and Belarus on top of general duties that already apply.

The tax hike will come into effect from April 25 alongside a prohibition on Russian oil and energy products.

Australia has also granted almost 5600 visas for people in Ukraine, with more of 1400 of whom have since arrived.

Ukraine's ambassador-designate to Australia Vasyl Myroshnychenko, who arrived in Sydney on Saturday after escaping Kyiv, expects the president will repeat calls to establish a no-fly zone over Ukraine during his speech.

The ambassador said Ukraine is concerned Russian missiles could inadvertently hit one of the country's five nuclear power plants, threatening the rest of Europe.

"If we have a no-fly zone (over parts of Ukraine) this is what is going to protect the sky and this is what is going to protect the safety and security of the entire Europe," he told ABC Radio.

"Despite any news that there is any progress in the peace negotiations we are very sceptical about the true nature and true intentions of Russia."

Mr Myroshnychenko said Australia should expel the Russian ambassador to send a statement of support for Ukraine.

"Every time I watch these harrowing pictures and footage from Ukraine (of bombings) ... I believe that the Russian ambassador should be expelled," he said.

It comes as a top United Kingdom intelligence official told the National Security College in Canberra that the Russian president has misjudged the resistance of the Ukrainian people, with Russian soldiers losing morale and refusing to follow orders.

"(Vladimir Putin) over-estimated the abilities of his military to secure a rapid victory," Sir Jeremy Fleming said.

"We've seen Russian soldiers - short of weapons and morale - refusing to carry out orders, sabotaging their own equipment and even accidentally shooting down their own aircraft."

Sir Jeremy, who heads the Government Communications Headquarters, also said Russia had turned to China for weapons, technology and as a means to circumvent sanctions.

But risks remain for the alliance into the future, he said.

"Russia understands that long term, China will become increasingly strong militarily and economically. If some of their interests conflict; Russia could be squeezed out of the equation.

"And it is equally clear that a China that wants to set the rules of the road - the norms for a new global governance - is not well served by close alliance with a regime that wilfully and illegally ignores them all."

Australia is providing $91 million in military assistance, $65 million in humanitarian assistance and 70,000 tonnes of thermal coal to meet Ukraine's energy needs, as well as temporary protection visas and support for Ukrainian community groups in Australia.

There are also targeted sanctions on individuals and entities, the prohibition of energy, oil and gas products from Russia, and a ban on exports of alumina and bauxite to Russia.

with Reuters

© AAP 2022

Ukrainian President Volodymyr Zelenskiy has told Australia's parliament the essence of the country's dream is still alive as he asked for more military aid.

To a standing ovation from parliamentarians and the viewing gallery, the defiant president appeared via videolink and proclaimed Russia's aggression as a real threat to Australia.

"That is the nature of evil - it can instantly cross any distance, any barriers, destroy lives," he said.

"Unpunished evil comes back with inspiration and a feeling of almightiness."

Mr Zelenskiy said the invasion of his country wouldn't have happened if Russia was held accountable for the shooting down of MH17 in 2014.

"We have to correct some horrible mistakes and correct them now," he said.

"We need new sanctions against Russia until they stop blackmailing other countries with their nuclear missiles. They have to pay the highest price."

The Ukrainian president asked for access to Australian military vehicles like the Bushmaster to help the country defend its territory.

"That could help Ukraine significantly - we would be very grateful if you could share those with us," he said.

Mr Zelenskiy also invited Australia to help with the restoration of the country's coastal cities.

"The geographical distance between us is huge, but what does this distance mean for those who have a common understanding?

"Geography doesn't matter."

Prime Minister Scott Morrison used his opening remarks to announce a further $25 million of defensive military equipment for Ukraine and to brand Russian President Vladimir Putin as the "war criminal of Moscow".

The package includes tactical decoys, unmanned aerial and ground systems, rations and medical supplies.

"Ukraine and Australia are separated by half the earth. Our languages, accents, histories and cultures are different but we share an affinity for democracy or freedom," Mr Morrison told the president and the parliament.

"Mr President, you have our praise. But you also have our weapons, our humanitarian aid, our sanctions against those who seek to deny your freedom."

Mr Morrison also pledged to help Ukraine rebuild following the war, praising the "strong people of an indomitable country".

Opposition Leader Anthony Albanese likened Russia's invasion to the devastation wrought by Hitler in World War II, saying Putin's aggression was prefaced by a "poisonous, nationalistic lie".

"As you stand up to this latest tyrant, you are showing us what true courage is," Mr Albanese said.

"It is the courage that is embodied by you (President Zelenskiy). You are fighting for your country and your people."

The government's aid package was announced alongside an additional 35 per cent tariff for all imports coming from Russia and Belarus on top of general duties that already apply.

The tax hike will come into effect from April 25 alongside a prohibition on Russian oil and energy products.

Australia has also granted almost 5600 visas for people in Ukraine, more than 1400 of whom have since arrived.

It comes as a top United Kingdom intelligence official told the National Security College in Canberra that the Russian president has misjudged the resistance of the Ukrainian people, with Russian soldiers losing morale and refusing to follow orders.

"(Vladimir Putin) over-estimated the abilities of his military to secure a rapid victory," Sir Jeremy Fleming said.

"We've seen Russian soldiers - short of weapons and morale - refusing to carry out orders, sabotaging their own equipment and even accidentally shooting down their own aircraft."

Australia is providing $91 million in military assistance, $65 million in humanitarian assistance and 70,000 tonnes of thermal coal to meet Ukraine's energy needs, as well as temporary protection visas and support for Ukrainian community groups in Australia.

There are also targeted sanctions on individuals and entities, the prohibition of energy, oil and gas products from Russia, and a ban on exports of alumina and bauxite to Russia.

with Reuters

© AAP 2022