SA Labor's long reign could end poll shows

More than half of South Australians say a change is needed after 16 years of Labor rule, according to a last-minute opinion poll.

After four successive Labor victories, 59 per cent of voters said the state was in need of a change, a poll by Reachtel revealed on Friday night, the eve of the state election.

The Liberal Party is expected to secure the most primary votes with 34 per cent of poll respondents showing support.

Jay Weatherill's Labor party had the backing of 31 per cent of responders while Nick Xenophon's SA-BEST is tipped to grab 16 per cent.

The remaining 19 per cent of responders are divided among the Greens, Australian Conservatives or are undecided.

Of those undecided voters 52 per cent would preference Labor over the Liberals on 48 per cent.