Film actor Heath Ledger's former girlfriend and Brokeback Mountain co-star Michelle Williams has arrived in Australia for the actor's funeral.

Dressed in black, Williams flew into Perth airport from New York with the couple's two-year-old daughter Matilda.

Williams, 27, and Ledger became a couple during filming of the gay romance, in which they co-starred as husband and wife.

They later moved to New York, and had Matilda, who was born in October 2005.

A handful of young people in casual wear were seen entering or leaving the house of Ledger's mother, Sally Ledger-Bell.

Ledger's parents and other close relatives arrived in Perth after spending nearly two weeks in the US immediately after his death.

Family members attended a memorial ceremony in Los Angeles at the weekend, but have kept funeral arrangements a closely guarded secret.

They are reportedly planning a private service in Perth and will either bury his body or inter his cremated remains in the city.

There was no indication that Ledger's remains have arrived in Australia. There was no sign of activity at the family's plot in Karrakatta Cemetery.

Ledger, 28, who was nominated for an Oscar for his role in Brokeback Mountain, died in his New York City apartment on January 22.

He had been filming scenes for The Imaginarium of Dr Parnassus at Battersea Power Station just before Christmas.