The Supreme Court of Canada has turned down a request by a coalition of human rights groups to review Ottawa's pact with the United States that has barred hundreds of would-be asylum seekers from filing claims in Canada.

The court's Thursday decision without comment, as is the norm, leaves the controversial "safe third country agreement" between the two countries in effect.

Under the 2004 agreement, refugees make their claims in the first of the two countries they enter. That means claimants trying to enter Canada through the United States would be turned back and told to make their claims in the U.S.

Critics have said the pact encourages more people to try to enter the country illegally and is unfair because the U.S. system is tougher than Canada's refugee process.

Ruling 'regretted,' says refugee rights group

The Canadian Council for Refugees, Amnesty International and the Canadian Council of Churches launched the challenge in 2005 in conjunction with an unnamed refugee claimant from Colombia, arguing the U.S. does not comply with the Convention against Torture and the Refugee Convention.

The coalition of rights groups scored a victory in 2007, when a Federal Court judge agreed and ruled the safe third country pact invalid. But that decision was reversed by the Federal Court of Appeal.

The president of the Canadian Council for Refugees said the top court's decision is "regretted," as it "means refugees will not have their day in court."

“The U.S. is not in fact safe for all refugees, so we deeply regret that the Supreme Court has not taken this opportunity to ensure that Canada provides refugees the protection they need from forced return to persecution,” Elizabeth McWeeny said in a release.

But in an email to CBCNews.ca, Alykhan Velshi, spokesman for Immigration Minister Jason Kenney, called the decision "an unmitigated victory for the rule of law."

Velshi said the agreement enables individuals to have access to a "full and fair process" for claiming refugee status in either the United States or Canada.

"We believe that through international co-operation with the United States, we can handle refugee claims in an efficient manner, reduce abuse of the system and share the responsibility of providing protection to those in need," he wrote.