TORONTO — The latest version of Canada's national pandemic influenza plan was released Saturday, the first official update of the plan in nearly two years.

It revises the document to reflect the real strides Canadian pandemic planning has made, Federal Health Minister Tony Clement suggested at a federal, provincial and territorial health ministers's meeting in Moncton, N.B., where the plan was unveiled.

But key and difficult issues -- whether to use limited antiviral drugs to prevent illness in essential workers and what kinds of masks to stockpile for health-care personnel -- remain to be ironed out in future drafts of the plan, admitted Dr. David Butler-Jones, the country's chief public health officer.

"The Canadian influenza plan for the health sector has been developed collaboratively by federal, provincial and territorial governments with input from key stakeholders,'' Clement told a news conference following the meeting.

"This updated plan is an excellent example of how -- together with the provinces and territories -- we can continue to advance our preparedness.''

New Brunswick Health Minister Mike Murphy said there are outstanding concerns about how much money the federal government will contribute towards pandemic preparedness -- but that these things can be "duked out'' over time.

"We now have to discuss how we are going to have some of these things funded and what the exact roles will be of the provinces and the federal government. But those issues are of secondary importance to the plan itself,'' said Murphy, who chaired the meeting.

"We'll probably do a little bickering ... but Canadians should sleep a little better tonight.''

The latest version of the plan builds on more than two decades of pandemic preparedness work that began in Health Canada offices shortly after the Swine Flu scare of 1976.

The updated plan, now 609 pages long, contains new sections on public health measures and surveillance. It also reflects the fact various levels of government have purchased significant supplies of antiviral drugs since the plan was first released in February 2004.

Clement said the new version also includes increased emphasis on pandemic planning for First Nations communities and reserves. There is more to come on that subject; Butler-Jones said an updated version of the annex on planning for First Nations communities should be issued in the next couple of months.

One notable change in the new version of the plan involves the dropping of a list of priority groups for antiviral drugs, drawn up when there was an assumption the drugs would have to be rationed.

In the past 18 months or so, Canada has significantly increased its antiviral stockpile. Just over five million treatment courses of the drugs are or will shortly be stockpiled in the country, with a goal of reaching 5.5 million treatment courses.

"We have enough or will have enough shortly that we think reflects the ability to essentially treat anybody who would seek treatment,'' Butler-Jones said.

Canada's plan is to use the drugs in the first wave of a pandemic, before vaccine can be made and before -- it is hoped -- the pandemic strain could develop resistance to the few anti-flu drugs in existence.

As well, early use of antivirals could work to reduce spread in the early days, Butler-Jones said _ in essence flattening out the peak of cases. That might help keep hospitals from being overwhelmed.

"That, coupled with public health measures, has the potential to dramatically slow (the virus's) spread, which also buys you more time (until vaccine is ready),'' he said.

Canada is still, however, looking at the issue of whether antiviral drugs should also be used for prophylaxis -- in other words, to keep key workers from becoming sick. That would require taking a pill a day, potentially for weeks, and would mean supplies could be stretched across fewer people.

Focus group-type discussions are currently being staged across the country so that planners can get a sense of whether Canadians believe the country's antiviral stockpile should be used for both prophylaxis and treatment or for treatment only.

Another contentious piece of guidance still in the works involves the type of masks hospitals ought to stockpile to protect workers.

There is a heated debate underway in Canada's public health and scientific communities over how influenza viruses spread. One side insists ordinary surgical masks should be sufficient protection in most cases and the other argues the more expensive N-95 respirators are needed to keep health-care workers safe.

U.S. pandemic planners recently urged hospitals to stockpile the more expensive masks, saying that while there isn't enough scientific evidence to say they will be needed, limited global production capacity makes it important to get orders in early.

Canadian planners are still looking at the question, Butler-Jones said.