A women's health lobbyist fears that Catholic doctors' refusal to prescribe contraceptive pills risks pushing the nation's already high teenage pregnancy rate even higher.

A Nelson Catholic and general practitioner has told 50 female patients that for religious reasons he will no longer prescribe artificial contraception.

Others in Auckland are considering similar action.

Auckland Women's Health Council co-ordinator Lynda Williams said yesterday that prescribing contraceptives to teenage girls when they sought them was vital.

Not doing so would increase teenage pregnancies, "unless they are given timely referrals and urged to go immediately to another provider".

"It's very much an opportunistic thing. You've got to seize the moment, not make them go off and make another appointment somewhere. Teenagers are very 'now' people."

She was also concerned about rural women missing out on services they wanted if their area's sole GP refused to provide them.

Nelson GP Dr Joseph Hassan, a 40-year-old married father of four, wrote to the 50 patients a fortnight ago telling them he would no longer prescribe contraceptives or refer women for sterilisation.

The letter, which listed doctors who would provide the services, told patients their fertility was a gift to be looked after and not something to be treated with medication like a disease.

"I have done this in response to a personal journey," he told the Herald. " ... I have been praying about God's direction on this in my life. Over the last few weeks, in various ways, I have felt this is the direction I should take."

Dr Hassan, who also opposes abortion and has set up a crisis support programme as an alternative, said he had long been troubled by the conflict between the Church's teaching on contraception and his medical practice. He said other doctors would prescribe contraception and his move would not increase the teen pregnancy rate, which was due to other factors, "not just a lack of contraception".

New Zealand has the third-highest teenage pregnancy rate in the developed world. In 2002, 3 per cent of female teenagers aged between 15 and 19 became pregnant.

Ms Williams said she was surprised by Dr Hassan's move. "It's really out-of-the-Ark stuff these days."

Dr Hassan said he knew of at least five other Catholic GPs who had had "a similar kind of journey to me".

Women's Health Action director Jo Fitzpatrick said she did not object to GPs following Dr Hassan's decision, as long as they made their stance known, so women did not turn up only to be refused.