NEW.BRUNSWICK (CBC) - New Brunswick's chief medical officer of health has released a large amount of an antiviral medication for people displaying symptoms of swine flu.

The move comes as flu clinics across the province are being cancelled and local health officials are battling with a shortage of the H1N1 vaccine.

The province is making Tamiflu available at pharmacies for free if people have a prescription from their doctor and believe they may have influenza.

The medication reduces the ability of the virus to reproduce, but does not give a person immunity to the H1N1 virus.

The antiviral could shorten the length of the illness and potentially reduce serious complications.

Public health officials predict more doctors will be writing prescriptions for Tamiflu in moderate to severe cases of swine flu.

Dr. Eilish Cleary, the chief medical officer of health, said she hopes Tamiflu will not be over-prescribed by doctors so the swine flu virus does not become resistant to the antiviral drug.

"If that was to become more prevalent, then we would see that Tamiflu wouldn't work for those people who really need it," Cleary said.

"So we recommend cautious administration of any medication and Tamiflu is no exception."

New Brunswick pharmacies have already received their supplies of Tamiflu and they were released for use last week.

Ron Jackson, a Fredericton pharmacist, said he and the pharmacists he has spoken to haven't seen a big demand for the antiviral drug.

"What I'm hearing around the province, there hasn't been a huge demand on the Tamiflu supply yet. I think that's a good thing," he said.

Another antiviral, Relenza, has been stockpiled by the province. It won't be released unless there are signs that the virus has mutated, and is resistant to Tamiflu.