Canada's decision to warn Canadians against travel to Mexico borders on hypocrisy, some critics are saying.

On Monday, the Public Health Agency Canada issued a travel advisory, urging travellers to postpone "elective or non-essential travel to Mexico until further notice." The U.S., France, Britain and Germany did the same.

The advisories fly in the face of advice from the World Health Organization. It notes that travel restrictions would have little effect, and could do more harm than good.

"We are very mindful that when you issue travel restrictions this can have many different effects: it can cause hardships for people; it can cause a lot of untoward effects," Keiji Fukuda, acting WHO Assistant General for Health, Security and Environment, said Monday.

Infectious disease specialist Dr. Neil Rau wonders why Canada, of all places, is ignoring the United Nations agency's advice.

"We're the country that campaigned to have the WHO decide what countries would be on travel alerts or not. We were incredibly irked to have Toronto circled during SARS. And here, we're not playing by our own rule book," he told Canada AM Wednesday.

Canada's chief public officer of health, David Butler-Jones, acknowledged that PHAC was aware of the economic implications of its decision.

"If you issue a travel advisory, not only are you impacting on a theoretical risk of exposure, but also the impacts of people not travelling -- what that does economically -- which then has health impacts," he said Tuesday.

Canada is only too aware of how travels bans hurt an affected country. When the SARS outbreak hit Toronto in 2003, tourism plummeted as everything from conventions to concerts was cancelled. Even residents stayed at home rather than out shopping. The city's economy lost about $950 million, a contraction of about 0.5 per cent, according to The Conference Board of Canada.

In Mexico, it is clear that swine flu fear is taking an economic toll.

In Mexico City, cancelled events and closed movie theatres, museums and other establishments are costing at least US$57 million a day, according to city's Chamber of Trade, Services and Tourism. That's a 36 per cent drop in revenue generated by tourism and services in the Mexican capital, chamber president Arturo Mendicuti said.

Numerous cruise lines have cancelled their port calls to Mexico, which relies heavily on tourist dollars.

While in the past, the WHO was quick to recommend travel restrictions to stem the spread of outbreaks, that changed with SARS.

"When we talk about travel advisories, we cannot think of the old days when we were dealing with SARS. It's a totally different ballgame now," said Margaret Chan, WHO director-general in a conference call Monday.

WHO faced sharply criticism for its warning against travel to SARS-affected countries, including Canada. Canada put enormous pressure on the agency to reverse its decision and retract the advisory, with telephone lobbying by Prime Minister Jean Chr�tien and several cabinet members.

With SARS, world health experts say that ultimately, the travel advisories probably limited the disease's spread. But in this case, WHO officials say the swine flu spread simply cannot be stopped.

"By definition, pandemic influenza will move around the world," Chan said. "Does that mean we are going to close every country? Does that mean we are going to bring the world's economy to a standstill?

"We know from past experience that transmission of influenza or the spread of new influenza disease would not be stopped by closing borders and would not be stopped by restricting movement of people or goods."