Roche Pharmaceuticals has temporarily stopped sales of its patented antiflu drug Tamiflu in Canada, saying it needs to safeguard its supply before influenza season begins.

Demand for Tamiflu increased sharply over the last few weeks as governments, individuals and businesses stockpiled the drug because of fears avian influenza outbreaks could trigger a global pandemic in humans.

"We saw more demand in one day last week than we saw for an entire flu season in the previous year," said Paul Brown, a spokesperson for Roche. The company said it is being responsible by managing world supplies, to ensure people who need the drug during the regular flu season are able to get it.

Once the regular season begins, the company said, it will release Tamiflu to hospitals and long-term care facilities for those at greatest risk of complications from the flu.

Roche's decision is probably prudent, said Jeff Poston, executive director of the Canadian Pharmacists Association.

"I think the concern that we have is that the responsibility to make that decision falls with the pharmaceutical manufacturer," said Poston.

Canada has stockpiled 35 million doses of Tamiflu, enough to treat 3.5 million people. On Tuesday, Dr. David Butler-Jones, Canada's chief public health officer, said five million more doses are on the way.

"That, I think, is enough to mitigate or manage the issue of potential premature or early mortality in an outbreak as we work to develop and distribute an effective vaccine at that time."

Federal Health Minister Ujjal Dosanjh agreed, saying Canadians should not be hoarding Tamiflu.

The stockpile plans assume Tamiflu will work against whatever virus ultimately causes a pandemic. Scientists say some strains of the current avian flu virus are already showing signs of resistance to the drug.