Same-sex marriages will be allowed in Nova Scotia following a ruling Friday morning that said banning them is unconstitutional.

Applause broke out in the Halifax courtroom as the Nova Scotia Supreme Court ruling made the province the sixth jurisdiction in Canada to allow same-sex couples to marry.

Earlier this month, a court in Manitoba made a similar ruling. Ontario, British Columbia, Quebec and the Yukon all allow gay and lesbian couples to marry.

Nova Scotia is the first Atlantic province to allow the marriages.

Justice Heather Robertson's ruling effectively changes the definition of marriage in Nova Scotia to "the lawful union of two persons to the exclusion of all others."

The couples who launched the court challenge are:

Brian Mombourquette and Ross Boutilier.

Kim Vance and Samantha Meehan, who were married in Toronto when Ontario legalized same-sex unions in 2003 and wanted to have their marriage recognized at home.

Ron and Brian Garnett-Doucette, who want to marry after being together for nearly 20 years.

After the ruling was delivered on Friday, the Garnett-Doucettes walked into a provincial office to file for a marriage licence. Confident the ruling would go in their favour, the couple had picked up wedding bands on Thursday.

"I can't express how excited I am," said Ron Garnett-Doucette, who's ready to plan his wedding.

To his partner Brian, the ruling means more than "just having what everyone else has and not having to fight for your rights all the time ... We are equal now."

Neither the federal nor Nova Scotia government opposed the challenge.

"We certainly did not want to waste taxpayers' money," said Nova Scotia Justice Minister Michael Baker.

The federal government tried to convince courts in British Columbia, Ontario and Quebec in 2003 not to change the definition of marriage, which Ottawa has jurisdiction over. It failed in all three cases.

In the Yukon case heard in July, the government didn't oppose the constitutional challenge, but asked for the challenge to be adjourned pending a Supreme Court of Canada review of draft legislation that would change the definition of marriage.

The court rejected that request, and ordered the federal and territorial governments to pay the plaintiffs' legal costs.

Nova Scotia has given gay and lesbian couples some marital rights since 2001 through a domestic partnership registry.

Premier John Hamm said on Thursday he would abide by the court's decision, but wouldn't say whether he supports same-sex marriages.

In New Brunswick, meanwhile, Attorney General Brad Green says his province won't recognize any marriage other than those between a man and a woman until the federal law is changed.