The number of people seeking asylum in Canada has fallen by as much as 40 per cent since the Safe Third Country Agreement came into effect.

The seven-month-old deal between Canada and the United States requires potential refugees to file claims in the first non-hostile country they reach after fleeing their homelands.

Many people who want to take shelter in Canada find it easier to travel by way of the U.S., so the deal means they must seek refugee status south of the border instead.

Citizenship and Immigration Canada says the number of claims filed at its land border offices in the U.S. has dropped by 40 per cent this year, compared to the same period in 2004. Numbers are down 23 per cent at the department's other offices, such as those located in airports.

The drop in claims shows the agreement that came into effect last December is working, said department spokesman Greg Scott.

"It was intended to help us to maintain our international obligation to protect refugees, but it was also to take action against those people who may be abusing the system," he said.

When the agreement was first proposed in 2002, Deputy Prime Minister John Manley said it would eliminate "the practice of asylum shopping by refugee applicants by allowing their return to the last safe country from which they came."

Mary Jo Leddy, the director of Toronto's Romero House, doesn't believe the decrease in claims is a result of a drop in bogus claims.

"We know that the Colombians who are desperate, who would be accepted here, are not going to be accepted in the U.S.," said Leddy, whose organization has been helping refugee claimants in Toronto for 15 years.

She said the agreement is about security, not refugees, adding: "We really have effectively closed the door to all but a few people."

Toronto immigration and refugee lawyer Lorne Waldman agrees.

"There's another reality, which is the number of refugee claims would have gone down anyway because of the new post 9-11 heightened security," he said.

It's only a matter of time before someone challenges the agreement in court, Waldeman said.

According to Citizenship and Immigration Canada, the overall number of people trying to claim refugee status has been falling steadily since 2001, from a total of more than 44,000 that year to more than 25,000 last year.

Critics blame the decline on the clampdown in security since the attacks against the United States on Sept. 11, 2001.