However, outgoing Premier Jay Weatherill has promised the party faithful this won't be the last time Labor reigns in SA.

"I'll just give you one pledge: we'll be back," he told them after conceding defeat in the state election on Saturday night.

A return in four years may already be on the party's mind but it has plenty of issues to grapple with in the immediate future.

These include whether Mr Weatherill will stay on as leader and if not, who will replace him, a question not dealt with in his concession speech.

Peter Malinauskas, who on Saturday was successful in his bid to move from the upper house to the lower house, is among those considered a potential successor.

It also remains to be seen exactly how many seats in parliament Labor will retain once all the votes are tallied.

The Liberals are likely to win at least 24 seats in the 47-seat parliament, enough to govern in their own right while Labor could finish with 18.

Despite the loss, outgoing treasurer Tom Koutsantonis was keen to stress on Saturday that the party was about more than campaigning.

"We are part of a movement, we're not a brand," he said.

"We're not Coke or Pepsi, we're about people's lives."

Australian Associated Press