The South Australian election campaign is officially under way giving the Labor government, the Liberal opposition and Nick Xenophon's SA-BEST party four weeks to woo voters.

Premier Jay Weatherill visited the state's governor on Saturday morning to get the campaign under way with the issuing of the writs for the March 17 poll.

Mr Weatherill looked relaxed as he drove into Government House ahead of a media conference later in the day, where he'll make his first real pitch for Labor to be returned for a record fifth straight term.

His focus on Saturday is expected to be the state government's recent fights with Canberra over health and education cuts and with Victoria and NSW over the Murray-Darling Basin Plan.

This year's election is shaping up as one of the most uncertain in recent memory with Mr Xenophon's party a strong chance of seizing the balance of power.

He will run candidates in more than 30 of the parliament's 47 lower house seats, and recent opinion polls suggest his group will attract plenty of support.

Also causing uncertainty at this election is a major redistribution of electoral boundaries that leaves the Labor government needing to increase its vote to retain office.

Mr Weatherill has said he's looking forward to the election campaign and asking South Australians to once again allow him the "privilege" of leading the state.

Liberal Leader Steven Marshall says it's time for a change and has urged voters to support his plan to attract investment and boost economic growth.

Mr Xenophon says if SA-BEST has the balance of power after the poll, he'll work to ensure South Australia continues to have stable government.