Hundreds of mourners are arriving at St Patrick's Cathedral in Melbourne to farewell entertainment legend Bert Newton at his state funeral.

The man affectionately known as "Moonface" died aged 83 on November 30 after his leg was amputated in May due to a life-threatening infection.

The Catholic requiem mass will be broadcast live on television networks Nine, Seven and Ten.

Prime Minister Scott Morrison is attending the service, as is Opposition Leader Anthony Albanese, while Premier Daniel Andrews will give a tribute on behalf of Victorians.

Dozens of TV and radio personalities are attending the mass including Andy Lee, Peter Hitchener, Sam Newman, Denis Walter and Tom Elliott.

Musical theatre star Rhonda Burchmore will read a passage from the Bible. Eddie McGuire will give a eulogy and broadcaster Philip Brady will read an Irish blessing.

Bert Newton's children, Lauren and Matthew, have written messages that will be read at the service. Matthew is in the US and won't attend in person.

Melbourne-born Newton started in radio aged 12 and scaled the heights of the Australian entertainment industry on stage and on screen.

Alongside Graham Kennedy and Don Lane, he was part of a trio known as The Kings of Australian Television.

A stalwart of Australian theatre, Newton performed in Beauty and the Beast, The Sound of Music, Annie, The Rocky Horror Show, Grease and Wicked.

Several Melbourne theatres dimmed their lights for one minute at 7.30pm on Thursday to honour Newton's contribution to the industry.

"Bert was a great professional and an esteemed colleague and friend," Her Majesty's Theatre owner Mike Walsh said.

Theatre producer John Frost said he was a "wonderful mentor to young performers".

"Thank you Bert for all the laughs over the years; our industry is a lonelier place without you," he said.

The four-time Logie winner mentored comedians Adam Hills and Rove McManus, who each remembered him in tributes on social media.

"Bert Newton was the ultimate entertainer. Australian TV wouldn't be what it is without Bert. It's up to us all to take what he taught us, and keep his spirit alive," Hills said on Twitter.

McManus said he had lost a "mentor and friend" and Australia had "lost an icon".

"But most importantly a family has lost their hero and soul mate. Sending love to all the Newtons, especially Patti. My heart is broken. Rest In Power, Albert Watson Newton," he said on Twitter.

Newton is survived by Patti, his wife of more than 46 years, his children and grandchildren.

© AAP 2021