A playwright's teenage daughters have told how they were encouraged to have sex with her friends in the 1970s.

Rozanna and Kate Lilley, now 55 and 57, were repeatedly raped and sexually assaulted at their mother Dorothy Hewett's bohemian house parties in Wollahara, east Sydney.

Their tormentors included film maker Bob Ellis, album cover artist Martin Sharp and British erotic photographer David Hamilton, who are all now dead.

Rozanna and Kate Lilley (pictured with their mother), now 55 and 57, were repeatedly raped and sexually assaulted at their mother Dorothy Hewett's house parties in Wollahara, Sydney

By the time the girls (pictured) were 16, Kate had slept with six men and Rozanna with 12

Their tormentors included film maker Bob Ellis, album cover artist Martin Sharp (right in 2013) and British erotic photographer David Hamilton (left in 2008), who are all now dead.

By the time the girls were 16, Kate had slept with six men and Rozanna with 12.

Both have now relived their horrifying childhood in new books, in which they describe their parents' home as a 'party house' and a 'brothel without payment.'

The sisters said they were victims of a culture of sexual freedom among the arts community which became predatory and that their mother would tell them sex was the greatest thing in life.

'People liked having us at a party,' Kate told The Australian. 'We were these nubile girls, we were interesting jailbait objects.'

They said dozens of famous men came through their mother's doors for the risque parties - and she, a left wing radical and feminist, encouraged them to join in.

It was unbearable at home,' Kate said, 'I used to have sex with men to prevent them having sex with Rosie. But then I would find out they did have sex with Rosie.'

Rozanna said she had sex with Sharp when she was 15 and that he phoned her decades later to say sorry.

Kate said she had sex with Ellis (pictured in 2002) 'whenever he turned up' at the house.

Rozanna (left) said dozens of famous men came through their mother's doors for the risque parties - and she, a left wing radical and feminist, encouraged them to join in. Hewett would also sleep with the men and her husband - the girls' father (pictured together) - would sleep with other women too

She also recalled how Hamilton once took close up shots of her vagina and breasts after convincing her to agree by showing her his child porn collection to prove that other girls had done the same.

Kate said she had sex with Ellis 'whenever he turned up' at the house.

Hewett, who died in 2002, would also sleep with the men and her husband - the girls' father - would sleep with other women too.

The shocking revelations come as the #MeToo movement continues to uncover sexual abuse allegations in the wake of the bombshell accusations against Harvey Weinstein.

Rozanna is now an anthropologist and autism researcher while Kate is a poet and associate professor of English at the University of ­Sydney.

Both have produced poems and books based in their harrowing youth.