Darren Millar AM says couples should be allowed up to three cycles of IVF
People in Wales should be able to have up to three cycles of IVF treatment on the NHS, an assembly member has urged.
The call from the chair of the Welsh assembly's health committee follows an embryo mix-up which denied a Bridgend couple the chance of another baby.
Darren Millar AM said Wales should follow the advice of a national health guidance group and offer three cycles, rather than the current one cycle.
The assembly government said its policy was to avoid variation between regions.
But Mr Millar, Conservative AM for Clwyd West, said that following the National Institute for Health and Clinical Excellence (Nice) guidance would increase the chances of successful pregnancies.
"You are missing out on the possibility of successful treatment because the assembly government has restricted it," he said.
"To be fair to them, they have done it because they wanted everyone to have access to some treatment.
"I want it to be in accordance with the Nice guidance and the Nice guidance indicates that there should be up to three courses of treatment."
The Welsh Assembly Government announced in 2005 that patients would be eligible for one cycle of treatment wherever they lived after people in north, mid and west Wales were denied treatment on the NHS.
An assembly government spokesman said: "In Wales, we have a consistent policy on access to IVF treatment whereas in England there remains variation between regions.
"Based on Nice guidelines, it was agreed that on balance, the fairest way to implement an equitable service across Wales, within the available resources, was to offer new and existing patients one cycle of treatment which would be subject to a number of criteria."
Debra and Paul received damages after a fertility clinic mix-up
He said the policy over access to fertility treatment brought in four years ago ended the "postcode lottery" which existed in Wales before the new guidelines.
"Whilst the Welsh Assembly Government recognises that one cycle of IVF treatment falls short of the Nice recommendation of three cycles, the budget position of the NHS in Wales does not allow an increased service at the current time beyond one cycle of treatment."
There have been complaints of a postcode lottery in England as not all primary care trusts (PCTs) there fund the recommended three cycles.
A survey of 151 PCTs in England in 2007 found 98 paid for one cycle of IVF, 32 funded up to two and seven funded up to three. Fourteen either did not fund IVF or did not provide details.
A couple from Bridgend have spoken of their devastation after a fertility clinic mix-up led to their last viable embryo being implanted into another woman.
Debra and Paul, from Bridgend, have received damages of about £25,000 after the error in December 2007.
Cardiff and Vale NHS Trust has apologised unreservedly and said its procedures had been changed.