Outgoing South Australian Premier Steven Marshall says he will resign the state Liberal Party leadership following last night's election loss.
Mr Marshall said it was a great privilege and honour to serve as South Australia's 46th Premier and lead his party for nine years.
"Whilst I am disappointed by the election outcome, I take full responsibility for the result and accept the will of the people," he said in a statement.
The Labor Party under leader Peter Malinauskas is set to form a majority government.
Mr Marshall will remain as leader until the partyroom meets to choose his successor.
He said he would continue to serve as the Member for Dunstan, in Adelaide's eastern suburbs, but he is facing a challenge from Labor's Cressida O'Hanlon.
The Premier led the two-party preferred count by 0.3 per cent as of midday ACDT.
"I thank all my past and current colleagues for their support over the past nine years and will do all that I can to assist the new Liberal leader to succeed," he said.
"I also look forward to continuing to serve the people of Dunstan."
Outgoing Deputy Premier Dan van Holst Pellekaan appears to have lost his seat of Stuart to independent Geoff Brock.
He was elected to the position last November after former deputy premier Vickie Chapman stood down while being investigated by the state's ombudsman.
Outgoing environment minister David Speirs competed for the deputy position.
He refused to comment on his leadership aspirations after the Liberals' election loss become apparent last night.
"At this stage I'm not going to comment on that. Steven Marshall is my friend," he said.
Prime Minister dismisses federal implications
Prime Minister Scott Morrison distanced himself from the state Liberal Party's loss, saying the South Australian election campaign was largely fought on local issues.
"My good friend Steven Marshall did a great job as the Premier and I’m looking forward to working with the new premier," he said.
Both Mr Morrison and federal Opposition Leader Anthony Albanese visited Adelaide twice in the lead-up to the election.
Mr Morrison was asked if he should be nervous about his own federal campaign after the result.
"This election was being fought on state issues, the federal election will be fought on federal issues and what I know is Anthony Albanese is not Peter Malinauskas; he's not any of the other premiers," he said.