OTTAWA - Thai authorities have arrested more than 100 Tamil migrants who were probably on their way to Canada, says Immigration Minister Jason Kenney.

Thai media reported Friday that 114 Sri Lankans were detained for being illegal migrants. Reports said many of the detainees had improper identification or none at all, and some were suspected of being linked to the Tamil Tigers. It was unclear if they were travelling by boat.

Kenney said the arrests -- along with proposed legislation to crack down on human smuggling -- should deter other migrants hoping to sneak into Canada.

"We understand that they ... detained over 100 illegal immigrants who apparently were planning on coming to Canada through a smuggling operation," Kenney said.

"We think this sends a strong message to the smugglers and their would-be customers that they should think twice."

Opposition critics said they were supportive of Canada helping to crack down on human smuggling, but urged the government to make sure the operations are not endangering the safety of asylum-seekers.

"Where we need to be careful is that that doesn't bleed over ... interfering with legitimate movement of refugees and migrants who are truly seeking to escape persecution," NDP public safety critic Don Davies said.

Kenney wouldn't say whether Canadian officials were involved in the arrests, but he made a point of highlighting increased co-operation between Canadian law enforcement and authorities in southeast Asia, especially in Thailand.

The co-operation is part of Ottawa's efforts to prevent ships of smuggled migrants from coming to Canada by disrupting their operations before they set sail.

"We acknowledge that the best way to stop boats from arriving in Canada is to stop them from leaving the transit countries in the first place," Kenney said.

"So local police action against illegally smuggling rings is essential. And for that reason we congratulate the Thai authorities for their alertness."

There was no immediate detail about charges against the detained Sri Lankans. In the past, Thailand has moved to deport migrants without proper documentation.

Canada has seen two boatloads of Tamil migrants land on its shores in the last year. When a ship carrying almost 500 Sri Lankans landed in Vancouver in August, Kenney and his cabinet colleagues promised a crackdown, both through legislation and by increasing Canadian co-operation overseas.

Earlier this month, Thai officials arrested more than 150 Tamil migrants in an operation that Canada may also have played a role in. But that's only the tip of the iceberg, Kenney warned.

"We're aware ... of more than one smuggling syndicate, very active, that are specifically targeting Canada, with the capacity to potentially bring several large steel-hulled vessels with hundreds of passengers each year," he said.

"Hundreds of people, we believe, have paid upfront fees."

The federal government is proposing new legislation that would impose stiffer jail terms on human smugglers, detain smuggled migrants for up to a year and put them on a type of probation for five years.

The aim is to scare off not just the human smugglers, but their customers as well. Ottawa wants to destroy the business model that makes human smuggling to Canada a profitable enterprise, Kenney explained.

But opposition parties have been reluctant to support the bill -- and the government's operations overseas -- for fear of penalizing legitimate asylum-seekers.

"I hope that it's a case of going after smugglers and that the hundred people arrested were indeed traffickers in human beings and smugglers, and not asylum seekers who are in a very vulnerable position," Liberal immigration critic Justin Trudeau said.

The Bloc Quebecois has said it will oppose the smuggling bill, while the Liberals and the NDP have reserved judgment, suggesting that they will propose amendments instead.