Usman Khawaja has celebrated the one-year anniversary of his return to the Test team with his fifth century in 12 months helping Australia to 4-475 against South Africa.

Khawaja was on the verge of his maiden Test double century when rain stopped play to end day two of the third Test, unbeaten on 195 after he and Steve Smith both struck tons.

Travis Head then motored along to 70 off 59 balls in an entertaining final session, continuing his swashbuckling summer, striking at more than 95 with an average of 87.5.

Having already wrapped up the series, Australia are now laying the platform for a 3-0 whitewash and the chance to lock in a spot in June's World Test Championship final.

Only rain looks likely to stand in their way, with more wet weather forecast on Friday and Saturday after a dark day one.

In superb form since he was recalled to Australia's team last January, Khawaja has averaged more than 75 since his comeback.

Unable to hold down a spot for the majority of his Test career, 36-year-old Khawaja is now enjoying one of the great late-career resurgences at the top of the order.

After resuming on 51no on Thursday, the right-hander worked the ball off his pads nicely and hit out-of-sorts spinner Keshav Maharaj over cover for six.

He also helped take 14 off one Kagiso Rabada over in the middle session, cutting the South African quick for four and then twice guiding him to the third-man boundary.

The one opportunity he offered up also went for four, middling Rabada to Anrich Nortje at point before the ball brushed the quick's pants and flew to the rope.

Smith, too, looked at home against the Proteas' bowling before becoming Maharaj's first victim of the tour on 104.

He had earlier cleared the rope off both of South Africa's spinners, dispatching Maharaj (1-108) over the legside and Simon Harmer back down the ground.

The former captain also looked comfortable against his old nemesis Rabada, playing a superb pull shot early to the boundary and doing again likewise off Marco Jansen.

He brought up his 30th century pulling Nortje for four, becoming the fourth Australian to reach the milestone.

Such was Australia's dominance, when Smith was caught and bowled by Maharaj, it was hard to tell if the batter or SCG crowd were more shocked.

Head soon took over.

He hit eight boundaries all around the ground and a big six down back over Maharaj's head, before eventually being caught off the bowling of Rabada (1-119) on the square-leg boundary.

South Africa's long day in the field adds to a lengthy list of tough days on this tour, with Maharaj and Rabada both poor and Nortje the only threatening bowler with two wickets on day one.

© AAP 2023

Australia's Chinese community is divided over a fresh round of travel restrictions as some question the politics behind the public health measures.

The federal government requires travellers to record a negative COVID-19 test within 48 hours of departure from the Chinese mainland, Hong Kong and Macau.

Medical experts have labelled the rules unnecessary.

Elena Collinson, a manager at the Australia-China Relations Institute, said the testing requirement was understandable but would have an impact on tourism and business ties, particularly in the lead-up to lunar new year.

"It is difficult to deny that there is some politicisation at play given the chasm between political action and medical advice," she told AAP.

The comments were echoed by Peter Low, a retired business figure from Brisbane's Australian Chinese community.

"My personal view is that they are overreacting. Why single out Chinese?" Mr Low said.

"It's similar to back when COVID first started - the Chinese were singled out and we copped a lot of flak, a lot of racial discrimination."

Chinese Australian Forum president Simon Chan said the travel rules were not unreasonable as there was a lack of information from Beijing about the outbreak.

He said Chinese travellers would also have more confidence in flying knowing they were less likely to catch COVID while in transit.

"You don't want to have a new variant coming in and then find out afterwards, it'll be too late," he told ABC radio.

Peter Ho, an honorary president of the Queensland Chinese Forum, initially thought the decision was political but told AAP he came to understand concerns held by global medical experts about a lack of information.

Kirby Institute associate professor Stuart Turville said it was too early to know if an descendant of the Omicron variant would bring more serious illness and hospitalisations.

"There is a lot of hysteria on social media saying this is the next big one," Dr Turville told AAP.

"Until the data is in hand, it's just crystal ball gazing."

There were no issues with compliance when the rules came into force on Thursday as Health Minister Mark Butler defended going further than measures suggested by the nation's top medical advisor.

"This modest, sensible measure that's been taken out of an abundance of caution is going to prove no hindrance, no barrier to that resumption of travel at all," he told reporters.

Mr Butler said the government hoped the test requirement would be temporary and many other countries had implemented similar rules.

"It's really important that the rest of the world have as much information as we possibly can get about this fast-developing COVID wave in China," he said.

China's foreign ministry has slammed the travel restrictions despite having the same requirement for entry.

Bendigo Chinese Association president Doug Lougoon said members of the community he'd spoken to were more concerned about the high cost of travelling to China as return airfares reached $4000.

"They'd be more worried about the cost of airfares rather than the imposition of a COVID test before they return," he said.

© AAP 2023

Australia's Chinese community is divided over travel restrictions on people entering the country, questioning the politics behind the public health measures.

The federal government is under fire for requiring travellers to record a negative COVID-19 test within 48 hours of departure from the Chinese mainland, Hong Kong and Macau.

Medical experts have labelled the restrictions unnecessary.

But Chinese Australian Forum president Simon Chan said while that may be the case, there was a lack of information coming out of Beijing.

He said Chinese travellers would also have more confidence in flying knowing they were less likely to catch COVID while in transit.

"You don't want to have a new variant coming in and then find out afterwards. It'll be too late," he told ABC radio on Thursday.

Kirby Institute associate professor Stuart Turville said it was too early to know if the Omicron-descendant would bring more serious illness and hospitalisations.

"There is a lot of hysteria on social media saying this is the next big one," Dr Turville told AAP.

"Until the data is in hand, it's just crystal ball gazing."

Elena Collinson, a manager at the Australia-China Relations Institute, said the testing requirement was "understandable" but would have an impact on tourism and business ties between the two nations, particularly in the lead-up to lunar new year.

"It is difficult to deny that there is some politicisation at play given the chasm between political action and medical advice," Ms Collinson said.

The comments were echoed by Peter Low, a retired business figure from Brisbane's Australian Chinese community.

"My personal view is that they are overreacting. Why single out Chinese?" he said.

"It's similar to back when COVID first started. The Chinese were singled out and we copped a lot of flak, a lot of racial discrimination."

China's foreign ministry has slammed the measures, despite having the same entry requirement, and threatened reciprocal measures.

Emergency Management Minister Murray Watt hit back, saying the measures were modest.

"That reflects the kind of policies that they've decided to take in relation to their own country," he told Sky News.

Senator Watt said the measures were only temporary.

"Hopefully, China will make a decision to become more transparent in its data sharing and provide information about genetic genomic sequencing," he said.

Liberal frontbencher Sussan Ley wants to know the rationale behind the measures, which were not recommended by the chief medical officer.

"It's not about (China), it's about what we do with our international borders," she said.

Bendigo Chinese Association president Doug Lougoon said members of the Australian Chinese community he'd spoken to were more concerned about the high cost travelling to China, with return airfares costing about $4000.

"They'd be more worried about the cost of airfares rather than the imposition of a COVID test before they return," he said.

© AAP 2023

Usman Khawaja has asserted himself as king of the SCG with another century to help Australia tighten its hold on South Africa in the final Test of the series.

Almost a year ago to the day, Khawaja's two-and-a-half year absence from Test cricket came to an end in the Ashes at the SCG, and he celebrated in style by twice knocking his way into triple figures.

The 36-year-old opener has picked up where he left off in the third Test against South Africa, bringing up his ton in the first session on day two.

He became only the fourth man, and second Australian, to score centuries in three consecutive Test innings at the SCG, after Wally Hammond, Doug Walters and VVS Laxman.

Khawaja has the highest average of any man who has played more than five Tests at the SCG and was 10th overall with 115.00 at the time he brought up his century.

He has posted the equal-second most centuries of any man at the SCG (four), trailing only Ricky Ponting, who managed six.

Right-arm spinner Simon Harmer gave left-handed Khawaja plenty to think about as he turned the ball with ease on day one.

But neither Harmer nor in-form paceman Anrich Nortje could remove him as David Warner (10) and Marnus Labuschagne (79) fell on a rain-affected day.

With more rain forecast, Australia needed to regroup on day two and make the most of their time in the middle before the wicket deteriorated any further.

The pitch is tipped to help spinners the longer the match goes on but the tweakers posed Khawaja few problems on day two.

He belted Keshav Maharaj over deep extra cover for the first six of the Test in a highlight of his innings.

On 94, he brought up his 13th Test ton with a four through the gully and then sprinted back for two runs after hitting to deep backward square leg on the next ball.

© AAP 2023