Melbourne psychologist Dr Janet Hall told the gathering of sex therapists that she had successfully freed several women from their sexual problems by hypnotising them.

Some of these women had a fear of sex sparked by a condition caused vaginismus, contractions which make intercourse painful and often impossible.

"I've found that with hypnosis you can get them to rehearse the sex act in the safety of their own imagination," Dr Hall told the conference in Sydney today.

"That way you can change their negative thoughts to positive and help them reframe the problem to show them there is a solution."

She said one Indian woman with a sperm phobia overcame her fear in three sessions and was now pregnant.

Another woman used the therapy to successfully overcome the fear that her husband was going to be "swallowed up" during sex.

Dr Hall said a patient in her 30s came to her after a nine-year sexless marriage and a "terrible anxiety" around intercourse.

"In hypnotherapy, she reverted to being age seven where a relative sexually abused her," the therapist said.

"She told me as if it was happening right then and there exactly what the perpetrator had done."

The controversial practice is dismissed by many as ineffective and even problematic but Dr Hall, who operates a private practice, said the benefits were clear.

She said she had not had such positive results from women suffering vulvodynia, or chronic physical vulva pain.

"I can't say I can wave my magic wand to dispel the pain, but it can be used to overcome their fear of penetration," the therapist said.

"Hypnotherapy has a lot to offer women who suffer in these ways and I really recommend those of you who work with them to explore it."

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