People line up for seasonal flu shots at a clinic in Calgary's Brentwood Village Mall. (CBC)

People lined up for seasonal flu shots in Calgary as Alberta Health Services opened free immunization clinics on Tuesday.

Lynn Schmidt, who lined up at the Brentwood Village Mall with her two daughters for about an hour, has been receiving flu shots for five years.

"I think that people are becoming more conscientious about the different types of flus that are out there and … preventive steps and preventive measures to help themselves physically," she said.

Dr. Judy MacDonald, Calgary's deputy chief medical officer of health, said she was pleased by the first day's turnout.

"I'm actually thrilled by the long lineups, and for people to come out on a day like today to get influenza vaccine really speaks to the importance that they attribute to their health," she said.

Flu clinics are being offered in four Calgary locations, with a focus on high-risk groups, which include pregnant women, people aged 65 or older and healthy children six months to 23 months old.

People who live in group settings like continuing care, and those with chronic medical conditions, are also urged to get the shot early.

However, anyone outside of those high-risk groups who attends one of the clinics will not be turned away, Alberta health officials said last week.

The seasonal flu shot will be offered until the H1N1 vaccine is available, expected to be mid-November. At that point, the province will change gears and vaccinate those over six months old, with people in high-risk groups encouraged to get their shot early.

The seasonal flu shot campaign will cost the province about $9 million, while the H1N1 vaccination has been estimated to run as much as $90 million.