Weinstein, 65, is accused of decades of sexual abuse and harassment by around 40 actresses, including stars Gwyneth Paltrow, Angelina Jolie and Mira Sorvino, Tarantino's ex-girlfriend.
Los Angeles police confirmed on Thursday that they are investigating Weinstein over an alleged sex attack that took place in 2013, the sixth such allegation against the producer.
The disgraced tycoon resigned from the board of The Weinstein Company this week, having already been sacked as its co-chairman.
Tarantino said in the Times interview he had heard about Weinstein's behaviour long before investigations by that paper and the New Yorker which prompted a flood of further allegations.
“I knew enough to do more than I did,” the Oscar-winning filmmaker told the New York Times, citing several episodes involving prominent actresses.
“There was more to it than just the normal rumours, the normal gossip. It wasn't second-hand. I knew he did a couple of these things.”
The director's ex-girlfriend Mira Sorvino told him Weinstein had made unwanted advances while another actress made similar allegations years later, according to the Times.
“What I did was marginalise the incidents,” Tarantino said, admitting that he had dismissed them as mild misbehaviour.
“Anything I say now will sound like a crappy excuse,” added the filmmaker, who won best screenplay Oscars for black comedy western ‘Django Unchained’ in 2013 and cult favourite ‘Pulp Fiction’ in 1995.
Weinstein and Tarantino have worked closely for decades since the producer distributed ‘Reservoir Dogs’ in 1992.
The pair also collaborated on ‘Pulp Fiction’, the ‘Kill Bill’ films, ‘Inglourious Basterds’ and ‘The Hateful Eight’.
