A cancer diagnosis takes a heavy toll on survivors' sex lives but there is something couples can do.

Cancer survivors should be talking about sex if they want to get their intimate lives back on track.

New research shows that the sex lives of most cancer survivors suffer after diagnosis and treatment, and that's true for all types of the disease, not just reproductive cancers.

But researchers say couples who talk about the sexual changes that follow a diagnosis are more likely to return to sexual intimacy.

A new survey of 657 cancer survivors shows 77 per cent suffered pronounced changes in sexual activity after treatment.

They reported a significant fall in sexual frequency, with 53 per cent of women and 41 per cent of men saying sex occurred never or rarely after cancer.

Almost half of all respondents rated their sexual relationship as unsatisfying, the survey by Western Sydney University found.

But researcher Professor Jane Ussher says there is something affected couples can do to regain their intimacy - talk about it.

"We found that people who talked about sexual changes with their partner were more likely to be sexually intimate after cancer," Prof Ussher says.

"This study shows the importance of health professionals acknowledging sexual changes and developing supportive interventions across the whole spectrum of cancer care."

Cancer survivors who want to reclaim their sex lives can also tap into the Rekindle program, which aims to understand and improve the sexual wellbeing of cancer survivors and their partners.

Rekindle, a joint partnership involving the Cancer Council of NSW and the University of Sydney, offers practical advice and teaches skills in a confidential environment to improve the sexual wellbeing of those who reach out for help.

It includes information on the side effects of treatment, overcomingfears and insecurities, communication advice for couples, and advice on the use of sex aids.