US comedian and actor Aziz Ansari has responded to an accusation of sexual assault by saying he had believed the encounter to be "completely consensual".

Babe magazine published a detailed account over the weekend from a 23-year-old woman who said she felt "victimised" after a date with Ansari.

She said it had taken her a long time to "validate this as a sexual assault".

Ansari has said he "took her words to heart".

The article published in Babe contained lengthy alleged details of the pair's date late last year.

The woman, under the pseudonym Grace, alleges that when they returned to Ansari's apartment after dinner last September, he repeatedly tried to initiate sexual activity.

She says he ignored or did not notice her signals that she did not want to have sex with him, and after several interactions which left her feeling "very uncomfortable" she left in a taxi in tears.

She said she later texted him to say he had ignored "clear non-verbal cues" and that he had responded at the time by saying: "Clearly, I misread things in the moment and I'm truly sorry."

'Surprised and concerned'

In a statement released through a representative, Ansari acknowledges that they went on a date and "ended up engaging in sexual activity, which by all indications was completely consensual".

He said the woman later told him in her text that "on further reflection, she felt uncomfortable".

"It was true that everything did seem okay to me, so when I heard that it was not the case for her, I was surprised and confused," he said.

"I took her words to heart and responded privately after taking time to process what she had said."

Ansari, 34, is a stand-up comedian, writer and actor. He has a Golden Globe and an Emmy for his series, Master of None.

Much of his comedy and TV work has focused on relationships, gender issues and women's rights, and he has been a vocal supporter of the Me Too movement against sexual assault and inappropriate sexual behaviour in the entertainment industry.

In his statement, he said: "I continue to support the movement that is happening in our culture. It is necessary and long overdue."