The couple have separated amicably after nine years of marriage, the Sydney Morning Herald said, with both determined to protect their two children, aged eight and six, from any publicity.

No comment has been made by Crowe, 48, or his Australian wife, 43.

Rumours that their relationship was in trouble surfaced in June this year when photos appeared showing Spencer on a night out with her Dancing with the Stars partner Damian Whitewood.

The pictures reportedly showed Spencer and Whitewood with their arms wrapped around each other in Sydney.

According to the Herald, Crowe is in the United States filming the biblical epic "Noah", while Spencer remains in Sydney with their two sons.

Other reports said the demands of Crowe's acting career may have been a factor in the split, with the star away for much of the past year filming Man with the Iron Fist, Les Miserables, Broken City, Man of Steel and Noah.

The pair first met 22 years ago on the set of the film The Crossing. They broke up and Crowe headed overseas to find work where he had a well-publicised affair with US actress Meg Ryan.

But he returned to Australia and proposed to Spencer, a singer, in 2002.

She is credited with helping tame Crowe, who is no stranger to controversy, famously throwing a telephone at a New York hotel concierge in 2005 when he could not get through to his wife in Australia.

He also pinned a British TV producer to a wall in 2002 for curtailing a BAFTA award acceptance speech. More recently, he apologised last year after an apparent anti-circumcision tirade on Twitter.

Writing in a Sydney newspaper in 2009, he said he had learned from his mistakes.

"In the past, I have put my parents and my wife, and my extended family, through some terrible times and I'm sorry for every moment of those public floggings that they have received the residual fallout from," he said.

The Herald said Crowe has earned about $150 million making films in the years since he married Spencer and speculated that she could conservatively walk away with a settlement of at least $25 million.

As well as being a Hollywood heavy-hitter, Crowe, who last year splashed out $10 million on a Sydney house to live in with Spencer, part-owns an Australian rugby league team.

He also has a luxury apartment in the city and a valuable 320-hectare rural property near Coffs Harbour, in New South Wales state.

Born in New Zealand, Crowe, who won an Oscar for his role in Gladiator, has lived in Australia since he was a child.