Japanese director Hirokazu Kore-eda won the Palme d'Or at Cannes on Saturday for "Shoplifters", a critically acclaimed family drama with unguessable plot twists.

The award, to a director who has won prizes at the festival before, defied speculation that the Palme might go to a female director, with three strong contenders in a year when the Hollywood sex scandal was the talk of the town.

Italian actress Asia Argento, who has accused movie mogul Harvey Weinstein of sexual assault, said there were abusers in the audience who had yet to be outed.

Argento said Weinstein raped her during the Cannes festival in 1997 when she was 21. "This festival was his hunting ground," Argento said in a speech ahead of the prize-giving.

Weinstein has denied allegations of non-consensual sex, and a lawyer representing him said that Argento's claims were completely false. Argento’s London-based agent, Steve Kenis, was not immediately available to provide further details.

"Even tonight, sitting among you, there are those who still have to be held accountable for their conduct against women," Argento told the black-tie ceremony.

"You know who you are, but, most importantly, we know who you are, and we are not going to allow you to get away with it any longer," she ended her speech, to applause.

Weinstein's attorney in Italy, Filomena Cusano, said the allegations by Argento were completely false, and that Argento and Weinstein had had a consensual relationship.

"This is clearly a painful time for Argento, but it is a false narrative," Cusano said in a statement. " Mr Weinstein only wishes Ms Argento well."

After the ceremony, Cate Blanchett who headed the jury of five women and four men, said: "Women and men alike on the jury would love to see more female directorial voices represented," adding that it had been "bloody hard" to select a winner.

"But in the end I think we were completely bowled over by how intermeshed the performances were with the directorial vision," she said of "Shoplifters".

The runner-up prize, the Grand Prix, went to Spike Lee’s satire "BlacKkKlansman", based on the true story of a black police officer who infiltrated the Ku Klux Klan in the 1970s.

Blanchett said the film's ending, with footage of the far-right rally in Charlottesville, Virginia last August and President Donald Trump blaming "both sides" for the deadly violence, "blew us out of the cinema".

A female director, Nadine Labaki from Lebanon, won the Jury Prize - effectively the bronze medal - for "Capharnaum", a realist drama about childhood neglect in the slums of Beirut.

Fifty years after he helped get the Cannes festival cancelled in 1968 in solidarity with worker-student protests, 87-year-old Jean-Luc Godard received a Special Palme d'Or for his collage of sounds and images, "The Image Book".

Poland’s Pawel Pawlikowski won Best Director for "Cold War”, a romance that moves from the peasant farms of Poland to Paris jazz clubs and back from the 1940s to the 1960s.

“Girl”, a Belgian drama about a transgender teenage girl’s quest to become a ballerina, won the Camera d'Or for the best directorial debut for director Lukas Dhont.

Jafar Panahi, the Iranian director who is prevented from leaving Iran and is in theory banned from making films, won Best Screenplay for "3 Faces" along with co-writer Nader Saeivar.

The award was given jointly to another film, "Happy As Lazzaro", written and directed by Italian Alice Rohrwacher.