Image caption Two other vessels carrying Tamil immigrants reached Canada within the last year

Canadian officials are investigating whether another ship is attempting to ferry Tamil migrants from Sri Lanka to Canada.

Authorities are using satellites to determine the location of the ship, the Toronto Sun newspaper reported.

In August, officials detained 492 Tamil migrants who arrived on board the MV Sun Sea from Sri Lanka.

Meanwhile, Prime Minister Stephen Harper has announced Canada will unveil a new law to deter illegal migrants.

Mr Harper said current laws in Canada did not go far enough to deter human trafficking, which he says "will increase in the years to come, unless we make significant changes to our law, to provide serious deterrents".

He called the trend in migrant ships attempting to reach Canada's west coast "unacceptable" and said he would unveil amendments to the immigration act designed to "ensure we deter this kind of behaviour".

Canada and Sri Lanka allege the MV Sun Sea migrants may include members of the Tamil Tigers, banned in Canada as a terrorist organization before their defeat last year.

Another vessel carrying 76 Tamil asylum seekers arrived in British Columbia in 2009.

Public safety ministry spokesman David Charbonneau said the most recent vessel was rumoured to be in international waters.

The coming winter months will bring stormy seas and freezing weather that will prevent ships from reaching the country, officials say.

Canadian immigration officials detained nine foreign nationals on Thursday, who were discovered hiding onboard a container ship that arrived at the Port of Montreal from Morocco.