A new study suggests most of the guns used to commit crimes in Canada have been smuggled in from the United States.

The study, published Wednesday in the Journal of Criminology and Criminal Justice, found that the best available data suggests that about two-thirds of crime guns seized in Canada have their origin south of the border. It's a situation the Americans would be unlikely to accept if it were reversed, said one of the report's authors.

"The U.S. never hesitates to draw attention to threats to its security," said Wendy Cukier of Ryerson University, one of the report's authors and a prominent gun control activist.

"Canada seldom points to the obvious fact that lax U.S. gun laws not only result in high numbers of Americans being killed with guns, but fuel the illegal gun trade and handgun homicide in Canada, in Mexico, in the Caribbean and indeed around the world."

The study, conducted by Cukier as well as researchers in the U.S. and Great Britain, looked at the underground market between the U.S., Canada and Mexico.

"It is not possible to determine with certainty the percentage of guns used in crime in Canada or Mexico that have been illegally exported from the Unites States, but there is some relevant evidence available that indicates the proportion is high," the study says.

"There are very few cases that show handguns used in crime coming from anywhere other than the USA."

In 2006, Toronto police successfully traced back 181 guns used in crimes to their original sale. The source of 120 of them was the U.S.

An Ontario-wide gun tracing program found that 69 per cent of 705 guns used in 2007 in crimes in that province could be traced to the U.S. About 90 per cent of those guns were either restricted or prohibited in Canada.

That same year, the Canadian Firearms Program reported that of the 710 guns used by criminals it was able to trace in 2007, 54 per cent were smuggled.

And last year, Canadian customs officials say they seized 514 restricted and prohibited weapons. Customs officials stop about three per cent of the traffic that flows across the border.

"The patterns seem well-established," said Cukier in an email.

Most of the smuggled guns - and guns used in crime - are handguns. The majority of rifles and shotguns used in crimes originate in Canada.

Criminal gangs are the recipients of most of the smuggled guns.

"Illegal trafficked weapons are primarily used by criminal groups of varying degrees of organization," the report says.

Still, it's tough to get complete data on the sources of guns used in crimes.

Many crime guns aren't recovered. Serial numbers are often erased and unrecoverable. And it's doubly difficult to track guns from countries outside the U.S., such as China, Cukier said.

Cukier said Canada should step up its efforts to fight gun-running.

"Canada should be taking a lead role in international efforts to combat the illicit trade in small arms," she said.

Canada has yet to ratify the UN Firearms Protocol, under which countries promise to do more to fight the illegal traffic in small arms around the world.