Canadians lined up for hours for an H1N1 vaccination on Saturday, overwhelming clinics and forcing some people to be turned away. (CBC)

Many flu clinics across the country had to close early Saturday as thousands of Canadians joined long lineups to get the H1N1 vaccine.

People lined up for hours as clinics were overwhelmed by the demand, forcing some to be turned away. Some people may have rushed to get their shot following the announcement earlier in the week that supplies would diminish next week.

Most clinics in Edmonton closed their lineups at about 12:30 p.m. local time, turning away new arrivals. All five clinics in Calgary stopped accepting patients by about 9 a.m. Some people had arrived as early as 4 a.m.

Alberta health officials later announced that the clinics have been suspended immediately because of a national reduction in the number of available vaccine doses. Officials said they will roll out a plan early next week for targeted H1N1 vaccinations, focusing only on those at the greatest risk.

At one of seven clinics in Ottawa, people started showing up shortly after 4:15 a.m. local time on Saturday. The clinic opened its doors at 9 a.m. By mid-morning, about 200 people were in line, many holding umbrellas in the rain.

Crowded Toronto clinics were immunizing about 200 people per hour as public health workers screened people in line before they made it to the door, trying to focus on those at highest risk of contracting the virus.

Many people were turned away as two of four clinics in Toronto shut their doors after being open for a few hours Saturday.

"There is only so many people we can see and only so much vaccine available, so stay tuned for more info on that," said Susan Blue from Toronto Public Health.

Hundreds of people were again lining up at swine flu vaccination clinics in Newfoundland and Labrador on Saturday amid word health officials have tightened the rules on who can get the shot.

On Friday, Canada's chief public health officer, Dr. David Butler-Jones, told a news conference in Ottawa that just over 400,000 doses of the vaccine will flow from manufacturer by the end of next week, down from roughly two million doses that were sent in each of the past three weeks.

Provinicial health officials are now warning Canadians that those who aren't in a high-risk group for complications from H1N1 shouldn't line up for vaccine.

Ontario's chief medical officer, Dr. Arlene King, said Friday that H1N1 vaccinations will only be given to Ontarians in priority groups next week, and the province will take a stronger line against people who don't fall into these groups.

The priority groups are:

• Pregnant women.
• Children from six months to five years of age.
• People who live with children under six months old.
• People under 65 with underlying medical conditions.
• Immuno-compromised people and those caring for them.
• People living in remote and isolated communities.

Health officials in other provinces are taking the same approach, she said.

On Saturday, Health Minister Yves Bolduc asked Quebecers to remain calm as the province rolls out its vaccination campaign.

Health officials say there will be enough of the H1N1 vaccine for everyone who wants to be inoculated but people will have to be patient as the province is adamant about following is priority list for vaccination.