All marriage commissioners in British Columbia have been told that any who aren't willing to marry same-sex couples must resign by the end of March.

Marriage commissioners received letters Tuesday from the B.C. Vital Statistics Agency advising them of the changes. The letters make no mention of what would happen if they refused to step down.

The agency asks those who plan to step down to let the province know by the end of February, so it can hire new staff.

The B.C. Court of Appeal altered the definition of marriage to "the union of two persons'' in May and lifted a moratorium on same-sex marriages in July.

There are roughly 300 marriage commissioners in B.C. and they perform about 54 per cent of the 22,000 civil marriages there every year. They are appointed by the provincial agency.

Ann Moore is a marriage commissioner who, over the last six years, performed hundreds of weddings -- 70 for gay couples since it became legal in B.C. last July. Ahe doesn't expect many of her colleagues will quit but admits some are upset.

"We understand there are some marriage commissioners who perhaps are not happy doing this, who have chosen, maybe for that reason or others to resign," she says. 

Advocates of same-sex marriage were delighted by the news.

"You can't drive a bus and not let people on because you don't agree with how they're dressed or what they're doing." says wedding consultant Taylor Darnel.

But opponents are blasting the Vital Statistics Agency's letter. B.C. Conservative MP Paul Forseth says the province appears to have has decided to "actively promote same-sex marriage as a matter of government operational policy." He worries that the province will now have to spend more time in court.

"Probably the marriage commissioners are going to get together and say 'No way' to the government and force the government to try to fire them," he told CTV News. "And the government is going to have to take its risk of a wrongful dismissal suit in court."

Forseth suggested a better alternative would be for commissioners to be organized into two groups: those who perform same-sex marriages and those who do not.