Troubled actor-director Mel Gibson walked away unharmed after crashing his Maserati into a rocky hillside in Malibu on Sunday (US time).

The accident involved no other vehicle and the Oscar winner was neither drunk nor under the influence of drugs at the wheel, police said in a statement.

"For unknown reasons, Mr Gibson steered his car to the right and struck the rock hillside," the statement said.

"His vehicle was towed from the scene, DUI is not suspected in the accident," it added.

The accident follows a troubled few weeks for the Australian-raised star, who is under investigation for domestic violence after his former partner Oksana Grigorieva released recordings of abusive telephone calls he allegedly made.

Gibson's driving habits made the headlines in 2006 when he was arrested at the wheel with 1.5 times the legal blood alcohol limit.

He was sentenced to three years' probation and fined $US1,300 after undergoing alcohol rehabilitation.

At the time, Gibson's arrest exploded into a major scandal when he made anti-Semitic remarks to the highway patrol.

- AFP