MISSISSAUGA, Ont. - Prime Minister Stephen Harper says the federal government "will not hesitate" to strengthen Canada's human smuggling laws, but after a week of suggesting a crackdown, the government has still not provided specifics.

Harper did not spell out what Ottawa might do to prevent future ships full of migrants from arriving in Canadian waters, similar to the way 492 Tamils arrived last week.

Public Safety Minister Vic Toews has been saying since last week that Canada will do whatever it has to do to beef up its laws and prevent human smugglers and terrorists from taking advantage of Canada's refugee system.

"Ultimately as a government we're responsible," Harper said Tuesday following a local announcement in Mississauga, Ont.

"It's a fundamental exercise of sovereignty. We are responsible for the security of our borders and the ability to welcome people or not welcome people when they come."

Harper noted Canada is a land of refuge, but when hundreds of people come to the country outside the proper channels, it leads to "significant security concerns."

"I think Canadians are pretty concerned when a whole boat of people comes, not through any normal application process, not through any normal arrival channel, and just simply lands and obviously this leads to significant security concerns."

Toews has suggested Canada will work closer with its allies to prevent future ships from even setting sail. Australia has also grappled with migrants arriving on its shores by ship.

Canada is a signatory to a United Nations declaration requiring countries to process refugee claimants at home.

Liberal MP Marc Garneau called on the Harper government Tuesday to show more compassion for the migrants, urging Toews to "lower the tone" of the government's rhetoric.

Garneau said since the MV Sun Sea arrived last Friday, the government has been fixated on suspicions that the ship is part of an organized human smuggling ring and that some of its passengers may be terrorists.

The migrants include 63 women and 49 minors — some of them very young children — and Garneau said Toews needs to remember that many may be genuine refugees.

Among the first of the migrants to appear at detention hearings in Vancouver on Tuesday was a young woman dressed in a dark-green sweatshirt and grey sweatpants, wearing sandals. Her hair was tied back in a bun and she sat still beside her lawyer, at one point glancing back at the dozen or so journalists sitting behind her.

She was brought in wearing handcuffs, but they were removed before the hearing began. When asked if she could understand the Tamil interpreter, she replied in Tamil that she could.

The hearing was told the woman came to Canada with her mother, father and brother and that she has family in Toronto.

She has given authorities what she said was an original national identification card and a birth certificate.

Ron Yamauchi, a lawyer for the Canada Border Service Agency, said her documents are still being authenticated and she was ordered to remain in detention.

Similar hearings continued throughout the day, with ten other women appearing in person and five more by phone. All were ordered detained while their identities are confirmed. There were all dressed in the same green and grey clothing.

The group of women included one who seemed to be much older with greying hair. One of the younger women appeared to be crying at one point. They sat still and listened intently as the hearing was translated into Tamil and they learned they would be sent back to a Vancouver-area jail.

Several had identity cards from refugee camps.

During the hearing by telephone, a child was heard in the background as five women listened from a youth detention centre in nearby Burnaby.

The Immigration and Review Board had set up temporary hearing rooms at a jail in Maple Ridge, where the male passengers were being held.

A total of 78 detention reviews were completed Tuesday.

The migrants say they've faced persecution in Sri Lanka since last year, when a decades-long conflict between the Sinhalese government and separatist Tamil Tigers came to a bloody end.

In an unsigned letter released by the Canadian Tamil Congress, the migrants say they have escaped mass murders, disappearances and extortion.

But Toews has said terrorists and criminals are believed to be among those on the MV Sun Sea. The Tamil Tigers are considered a terrorist organization in Canada.

Garneau said the government hasn't been balanced.

"If you look at (the reaction of) Mr. Toews, there's a little bit too much on terrorism and human trafficking and not enough perhaps to indicate, I would say, a little bit of a level of compassion," Garneau told a news conference in Ottawa.

"So just a sense of proportion on this whole thing would be nice."

Garneau added that the Liberals agree the government should prevent terrorists and human smugglers from abusing Canada's generous refugee system.

But he added that the government shouldn't over-react, noting that the latest ship-borne arrivals represent only about two per cent of the refugee claimants who arrive in Canada each year, most of them at airports.

Federal NDP immigration critic Olivia Chow said the best way for Canada to ensure no more migrant ships depart from Sri Lanka is to work on ending suffering in that country.

The NDP accused Ottawa of simply moving on from the Sri Lanka file after the bloody civil war ended there last year.

Yamauchi told the hearing the agency has briefly interviewed all 492 migrants, and photographing and fingerprinting has begun.

He said any documents handed over by the migrants will be analyzed by experts, and the CBSA has brought in extra staff to help process claimants.

"I submit we are taking every effort that we can to establish identities as quickly as possible," he told the detention hearings in Vancouver.

Detention hearings are usually held in private, but members of the media argued the hearings are in the public interest and should be open in this case.

Leanne King, a member of the Immigration and Refugee Board, agreed Tuesday, but with conditions. The migrants' names, ages, places of birth and other identifying details can not be reported.

King denied access to members of the Canadian Tamil Congress and the Transnational Government of Tamil Eelam, saying they can get their news from reporters.

— With files from James Keller in Vancouver and Joan Bryden in Ottawa