South Australian doctors encourage flu jabs amid spike in cases statewide

South Australia's peak flu season has arrived, with the number of cases spiking across the state. 

In the past week SA Health has recorded 249 cases, compared to 151 a fortnight ago. 

So far this year, there have been 2604 cases of flu compared to 20,980 cases last year, which was South Australia's worst flu season on record.

Doctors say despite the 2018 season arriving, it's not too late to receive a vaccination.

"I would urge anyone who hasn't already got a flu shot this year to go to a GP or pharmacy and get one now," Dr Louise Flood of SA Health said.

"It takes about two weeks for the vaccine to be effective, so it's not too late."

There were fears supplies of the flu vaccine were falling short of the demand earlier this year, but authorities are assuring the public availability has increased.

"There has been high demand for the flu vaccine this year and a national shortage at the beginning of the season," Dr Flood said.

Vaccinations are available at your GP and most pharmacies. Some members of the public may also be eligible for a free jab under the National Immunisation Program.

They include those aged 65 and over, pregnant women, Aboriginal and Torres Strait Islander people under the age of five, or 15 or over and people with underlying medical conditions. 

Children aged six months to five years also are eligible for free vaccinations.