A group that has been helping Tamil migrants who arrived in Canada last month says "sensitive information" has been stolen from its offices.

The Canadian Tamil Congress says someone broke into the Toronto office sometime overnight, and stole a computer.

The congress says it contained the names and information of hundreds of migrants.

A spokesman for the congress, David Poopalapillai, says it was a "deliberately targeted attack," because other computers and a flat screen TV were left behind.

The identities of the migrants are subject to a publication ban ordered by the Immigration and Refugee Board.

Toronto police will only confirm there was "an entry" at the office, but officers are still trying to determine exactly what has been taken.