Friends and family of actor Philip Seymour Hoffman have paid their respects at a funeral in New York City.

Among those at the Church of St Ignatius Loyola were Meryl Streep, Cate Blanchett, Ethan Hawke, Spike Lee and other show business figures.

The Oscar winner was found dead at his home in Manhattan on Sunday with a syringe in his arm.

While police believe Hoffman, 46, died of a heroin overdose, a post-mortem examination was inconclusive.

The New York City medical examiner's office has said more tests are needed to determine what exactly killed Hoffman.

Authorities also found dozens of bags of what seemed to be heroin in the actor's apartment.

Hoffman's partner of 15 years, Mimi O'Donnell, and their three children walked behind the coffin as it was brought into the church on Friday.

Playwright David Bar Katz, who found Hoffman's body, looked visibly upset as he arrived before the funeral.

The lights at theatre marquees on New York's Broadway, the centre of American theatre, were dimmed on Wednesday in Hoffman's honour, and a candlelight vigil was held outside the Labyrinth Theater Company. His close family held a private wake on Thursday.

A larger memorial service is being planned for later in February.

Amid the investigation into the actor's death, three people have been arrested on drug charges, including one on a charge of heroin possession with intent to sell.

Lawyers for all three deny the suspects had anything to do with Hoffman's death.

Hoffman had previously spoken about his struggle with drug addiction. After 23 years of sobriety, he reportedly checked himself into a drug treatment programme for 10 days last year after relapsing in 2012.