Australian actor Heath Ledger has been found dead at his New York home after a suspected drug overdose, US police say.

The Brokeback Mountain star was found naked and unconscious at an apartment in Soho on Wednesday afternoon by a housekeeper who went to remind him about a massage appointment.

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Emergency services were called, but attempts to revive the 28-year-old failed, and he was pronounced dead at the scene.

"We are investigating the possibility of an overdose," New York Police Department spokesman Paul Browne said. "There were pills in the vicinity of the bed."

But his family have denied any claim the actor would have killed himself. Speaking to reporters outside their home in Perth his parents, Kim and Sally, and sister Kate said his death was "very tragic, untimely and accidental".

Relationship split

They said the "dearly loved son, brother and doting father" had been found "peacefully asleep", adding that he was "a down-to-earth, generous, kind-hearted, life-loving unselfish individual, extremely inspirational to many".

Police earlier said it was too early to rule out foul play, or to decide whether any overdose was accidental or a deliberate suicide attempt. There are also reports he may have been suffering from pneumonia.

"That's what needs to be investigated," said NYPD officer Martin Brown. "It takes a while, the medical examiner will do an autopsy and they will determined the cause of death."

Ledger split with fiancee Michelle Williams, who he met on the set of critically-acclaimed cowboy flick Brokeback Mountain, last year. The pair have a daughter, Matilda, who was born in October 2005.

The actor was born in Perth, Western Australia, the son of a French teacher and a race car driver and mining engineer.

He rose to fame in a string of independent movies, and has recently finished filming the role of the Joker in Batman Begins sequel The Dark Knight, which is due for release later his year.

Oscar nomination

After moving to Sydney in his late teens, and netting early TV roles in shows including Home and Away, he got his big break in Australian crime drama Two Hands, which led to a role in teen comedy 10 Things I Hate About You.

He went on to play the suicidal son of Billy Bob Thornton in Monster's Ball and had leading roles in A Knight's Tale and The Patriot, as well as the AFI-winning Candy, in which he took on the role of a heroin addinct.

He was nominated for an Oscar for his role as gay cowboy Ennis Del Mar, opposite Jake Gyllenhaal - who became godfather to his daughter - in Brokeback Mountain, adapted from a short story by E Annie Proulx.

Film critic Margaret Pomeranz told the ABC she was devastated by news of his death.

"I am so upset... he's such a talented boy and I really think a beautiful soul. I think to choose the roles he's chosen just showed such intelligence."

Ledger had previously had a two-year relationship with fellow Australian star Naomi Watts, after the pair met during the filming of Ned Kelly in 2002.