With SA due to go to the polls of March 20, the state's electoral commissioner Kay Mousley said an estimated 88,000 people who were eligible to vote were not enrolled.

Most of those were people who had moved and not updated their details and 18 to 21-year-olds who were yet to sign up.

"With the state election due on March 20, we are keen to find as many of these people as possible and get them enrolled," Ms Mousley said today.

"Once the writs for the election have been issued by the governor, there will be only 10 days left for people to act."

While the date for the election is set, the government can ask for writs to be issued any time between now and February 20, one month before the poll.

Ms Mousley said recent legislative changes also made it compulsory for all eligible voters to enrol and that meant all Australian citizens aged 18 or over and who had lived at an address for at least a month.