‘We were really surprised by that finding,’’ said Amanda Ralph, spokeswoman for Marie Stopes International Australia, a sexual health service that provides contraception advice and performs abortions, vasectomies, and testing for sexually transmitted infections.

‘‘We see a lot of women coming in with unplanned pregnancies. Some of that is due to contraceptive failure, but some of them may have been using unreliable forms of contraception.

‘‘In the context of both unplanned pregnancy and STI prevention it’s very worrying that such a significant percentage of men are using withdrawal or rhythm method.’’ More than 60 per cent of those surveyed believed it was important for men to take responsibility for contraception.

However, only 11 per cent said they would ever undergo a vasectomy. The study, funded by Marie Stopes International Australia and conducted by Quantum Market Research, found a fear of pain prevented many men from considering having a vasectomy.

‘‘The overwhelming myth that prevented men having a vasectomy was the perception of the pain, with 24 per cent believing that having the procedure would be very painful,’’ Ms Ralph said.

‘‘But when we asked the subgroup of men who had had a vasectomy about it, they were more likely to strongly disagree that it was a painful procedure.‘‘A lot of men don’t have an understanding of what the procedure entails and what it means anatomically for them.’’

Ms Ralph said men often relied on friends, magazines or the internet to find information on sexual health, rather than more reliable sources such as doctors. Only half of men said they had ever discussed contraception and sexual health with their doctor.

But Australasian Men’s Health Forum president John Macdonald said health regulators and doctors needed to find ways to encourage men to seek advice. ‘‘We should be trying to make medical services more male-friendly rather than just blaming the men,’’ he said.