Some of the strikers are refusing everything -- they won't even take a sip of water.

One, a woman being held in Burnaby, has already been admitted to hospital for dehydration.

Corrections official Sheldon Green said food and drink is being offered on a regular basis to the hunger strikers.

Immigration Canada says the migrants are being held for a good reason, and the hunger strike won't bring a change of policy.

Officials point to earlier migrants who were released, then never showed up for their refugee hearings.

The migrants have been held in detention for almost four months.

The migrants arrived illegally by sea, starting in July. After a brutal passage on crowded and unsanitary ships, they ended up in detention, waiting for hearings on their applications to be considered refugees.

In all, 599 people came on four ships. Almost all sought refugee status. Not one of them has succeeded, but not one has been deported, either.

Tuesday, a small number of protesters gathered outside the federal immigration office in Vancouver. They say it's unfair to keep the migrants locked up indefinitely.

"They're saying, 'We want to be released. We're not criminals, so what are we doing in jail for four or five months?'" said refugee advocate Nandita Sharma