Temporary work permit rules will be tightened up and travellers from Canada will be grilled by Immigration officials about their health in a bid to block the spread of a killer pneumonia-like infection.

Applicants for short term work permits from virus-hit countries will have to provide a medical certificate as Assistant Chief Immigration Officer Rozy Azhar said Bermuda was leaving nothing to chance.

She said medical certificates had normally only been requested for those applying for work permits of one year or more.

She said: "Now we are asking for a medical certificate for all temporary applicants of those coming from areas that were at risk."

Canada is now requiring passengers leaving Toronto to fill in questionnaires after three deaths from the disease.

Ms Azhar said travellers who had also gone through other disease hot spots would be questioned in Bermuda.

The World Health Organisation on Thursday stressed the need to screen travellers in places where deaths have occurred from the virus, including the southern Chinese province of Guangdong, neighbouring Hong Kong, Singapore, Vietnam and Toronto.

There are now 28 probable cases in Ontario of the disease known as SARS, with another 10 suspect cases and 21 under investigation.

SARS, which scientists say is caused by a new virus strain, first showed up in China late last year, where it left 34 people dead.

Canada is now quarantining hundreds of people in their homes to combat the mysterious respiratory disease. More than 1,000 are battling for their lives worldwide and 53 have died.

Ms Azhar said: "We will ask them questions to satisfy ourselves whether or not they have been ill."

She said Immigration had consulted with the Chief Medical Officer who had suggested questions.

"If someone appears to be ill with an infectious disease under our act we have the authority to refuse landing."

Arrivees will be asked if they have been in an illness affected area in the last two weeks and whether they have been ill in the last two weeks.

She said Immigration officers would have to strike a balance at the airport.

"We can't give the third degree to all tourists," she said.

But if someone looks like they have symptoms they would be quizzed further.

She said the policy had begun on Thursday - the day of the World Health Organisation's warning.

Very few arriving visitors had been denied entry because of illness over the years said Ms. Azhar. "You don't stop everyone with a cough or a cold."

She said airlines normally blocked ill passengers beginning their journey if they had obvious diseases such as measles or chicken pox.

Chief Medical Officer Dr. John Cann said it was important people not panic about SARS.

He said people affected so far had been health care workers and families of people looking after people with the disease.

"They are at increased risk. There's really no reason for people to panic."

He said hand-washing and good hygiene had helped counter the disease abroad.

And he said if the disease did reach Bermuda, there were contingency plans in place to deal with it.