The Harper government is considering how to make divorce possible for same-sex couples who had to come to Canada to get married.

Thousands of gays and lesbians who could not marry in the country where they live have travelled to Canada seeking a legal marriage. But Canada's divorce laws don't allow people who haven't lived in Canada for at least a year to end their marriage.

In a statement to CBC News, Justice Minister Rob Nicholson said he would be "looking at options to clarify the law so that marriages performed in Canada can be undone in Canada."

Earlier Thursday, Prime Minister Stephen Harper insisted his government doesn't want to reopen the debate over same-sex marriage, despite newly-revealed legal arguments from a federal lawyer that a same-sex marriage performed in Canada is not valid if it isn't recognized as legal in the place where the couple lives.

"When we first came to office we had a vote on this issue. We have no intention of further reopening or opening this issue," Harper said at a shipbuilding announcement in Halifax, adding that he did not know the details of the government's submission in this case.

At a second shipbuilding event in B.C., the prime minister reiterated his position, saying the law "recognizes same-sex marriage in Canada and the government is not going to reopen that issue."

The renewed attention was sparked by the case of an unidentified lesbian couple who married in Canada in 2005 but split up in 2009. The partners are living in Florida and the United Kingdom. Both women want a divorce, but cannot get one where they now live because the state of Florida does not recognize their marriage, and although the U.K. grants civil partnerships to same-sex couples, it does not recognize the Canadian marriage.

The couple went to court last June seeking a Canadian divorce, despite the federal Divorce Act's one-year residency requirement, which they do not meet. Their submission argues the rules are discriminatory, and the couple is seeking $30,000 in damages for negligent misrepresentation by the province of Ontario if their marriage is found to be invalid.

But in addition to the residency requirement, a submission from a federal government lawyer in response to the couple's case cites another reason for refusing to grant the divorce — that they are not legally married.

'In this case, neither party had the legal capacity to marry a person of the same sex under the laws of their respective domicile — Florida and the United Kingdom. As a result, their marriage is not legally valid under Canadian law.' —Sean Gaudet, federal government counsel

Documents released Thursday show the government arguing that "in order for a marriage to be legally valid under Canadian law, the parties to the marriage must satisfy both the requirements of the place where the marriage is celebrated... and the requirements of the law of domicile of the couple with regard to their legal capacity to marry one another."

Residency required for divorce

Canada's marriage laws do not have a residency requirement. But federal divorce laws do.

Same-sex couples who travel to Canada to marry because the jurisdiction in which they live does not marry gays or lesbians run the risk of not having the legal means to divorce if the relationship sours.

The couple's submission to the court argues that this is an "unintentional gap" not contemplated by legislation that should be rectified by the courts.

The couple's lawyer, Martha McCarthy, told Toronto host Matt Galloway on CBC Radio's Metro Morning that the government lawyer's argument in this case came as a shock.

"[I was] very surprised... Fell off my chair surprised," said McCarthy, a prominent Toronto lawyer with a long history of involvement in same-sex marriage cases.

Although McCarthy does not think the same-sex marriage issue is alive as a political issue again, she does think the position taken by the government lawyer in this divorce case is a concern, suggesting that the government's attempt to differentiate between residents and non-residents in recognizing the validity of a marriage may be a case of the government doing what is "politically expedient."

"I hope [the federal government lawyer's] position is not succesful. If it is it will be a significant embarassment to us all," McCarthy said. "Embarassment...to us as a nation, who have been a leader in equality rights for gays and lesbians since this issue became an international one."

Harper declined to comment on the details of the government lawyer's arguments in this particular couple's case, suggesting he needed to be briefed on the specifics.

"I am unaware of the details. This I gather is a case before the courts where Canadian lawyers have taken particular positions based on the law. But I will be asking officials to provide me with more details," Harper said in Halifax.

A senior government source told CBC News Thursday that the prime minister's office was unaware of the submission until it came to light in a media report.

Opposition concerned

NDP MP Olivia Chow said the government was sending confusing signals about whether it really supports gay marriage.

"I think that Mr. Harper is hiding behind the law and using a back-door way to say to these loving couples 'sorry, we no longer recognize your marriage' and that is hugely embarrassing and makes Canada a laughing stock in the world," Chow told reporters.

Heading into their caucus meeting on Thursday morning, some Liberals, whose party was in power when same-sex marriage became legal in Canada in 2005, were accusing the Harper government of quietly using a court proceeding to erode equality rights.

"This is what we have been worried about with the Conservative majority for a long time, we're going to see the erosion of gains we've seen in this country," said Quebec Liberal MP Justin Trudeau, noting that an Ontario Conservative MP, Stephen Woodworth, has also been trying to bring abortion rights onto the public agenda lately.

Interim Liberal leader Bob Rae said that "it seems passing strange to me now that this would be the new position of the government of Canada."

"We've literally encouraged and allowed people to come to Canada to get married, and to turn around now and say we were only kidding, this wasn't a real marriage... That argument doesn't make sense to me," Rae said.

Rae also didn't fully accept Harper's explanation that he wasn't aware of what a government lawyer had written in this case. "I would be surprised if the PMO was unaware of it, but I have to take the prime minister at his word when he says what he says."

Government also not recognizing foreign civil partnerships

Last August, the federal government also gave notice it will intervene in a divorce case concerning a gay couple who now live in Toronto.

The couple, which includes a Canadian citizen, have a civil partnership registered in the United Kingdom, but are seeking a divorce in Canada. In its intervention, the federal government is arguing that the partnership is not equivalent to a Canadian marriage, and therefore the couple are not recognized as spouses in Canada and not eligible under the Divorce Act.

In both cases, the relationships between Canadian marriage and divorce laws and federal jurisdictions are in question.

Gay and lesbian rights advocates Égale Canada have lobbied Justice Minister Rob Nicholson to recognize a foreign civil union such as this as equivalent to a Canadian same-sex marriage in the eyes of the law.

"Why is the federal government using public resources to diminish the effects of other countries' efforts to provide same-sex couples with equality?" wrote Égale's executive director Helen Kennedy in an open letter to Nicholson in October.

"We have been very clear that we are not reopening the issue, but it is a legal dispute over definitions," Nicholson told the House of Commons last fall.

With files from CBC News