The bill would force medical staff to treat patients of their own sex only.

An earlier vote last month was rejected by the higher state body, the Guardian Council, on the grounds that it would increase public expenditure without providing the necessary sources of income.

But the conservative-dominated parliament has now passed an amendment to ensure funding.

The proposal seems to have become another battle in the power struggle between the conservatives and the moderates in the Iranian leadership.

Supporters of President Khatami say the conservatives' insistence on passing the legislation at any cost is designed to undermine the government. But observers believe the plan may backfire.

The BBC's Iranian Affairs Reporter, Sadeq Saba, says most people see the plan as backward and dogmatic. A liberal Iranian newspaper has said this is one of the rare cases that legislation is opposed by almost everybody except a group of hardline conservatives who are behind it.

Full segregation

The bill would require all private and state hospitals to segregate fully all health services offered to men and women in accordance with strict Islamic regulations.

Only female staff would be allowed to treat women, and male patients would have to be treated by men. Offenders would face heavy fines and the loss of licences.

The Guardian Council is to reconsider the bill before it becomes law.

'Lives at risk'

The idea for segregation was first raised after the Iranian revolution 20 years ago, but was abandoned because there were not enough women doctors.

Some hardline conservatives continued criticising Iranian hospitals for failing to respect Islamic restrictions on contact between the sexes.

The conservatives first proposed the bill to parliament last April and it immediately caused an outcry in the country.

The health ministry opposed the measure, saying it was costly and impractical.