Kyam Maher to be deputy premier after Susan Close, Stephen Mullighan to quit politics

South Australia's Attorney-General Kyam Maher will replace Susan Close as deputy premier after the latter and Treasurer Stephen Mullighan revealed they would quit politics.

An emotional Premier Peter Malinauskas announced the departure of Ms Close and Mr Mullighan during an unexpected press conference.

Later on Thursday, SA Labor Party in a statement said Mr Maher has been elected as deputy leader of the party and would be sworn in as deputy premier on Friday.

It said member for Adelaide, Lucy Hood, and member for King, Rhiannon Pearce, had also been elected cabinet roles while member for Elder, Nadia Clancy, would serve as an assistant minister.

Ministerial portfolios will be allocated at a ceremony at the Government House on Friday morning.

The premier said Ms Close and Mr Mullighan came to him with the news separately a few weeks ago.

"I've known Susan and Stephen for a long time and they're good friends of mine and they've been [an] incredible support to me in different ways over the last few years and I'm really sad to see them go," Mr Malinauskas said.

"I'm here today to make it very clear that my persuasive powers failed, and they have both announced their resignation to our cabinet earlier today from cabinet and their intention to not contest the next state election."

'Life is finite and it's precious'

Ms Close was elected in 2012 to the seat of Port Adelaide while Stephen Mullighan won the seat of Lee in 2014.

Ms Close said she had been considering whether to end her political career at the March 2026 or the following state election.

"I decided it's this election and I decided it because I feel that probably I've given more than I have yet to give in this role," she said.

"Life is really short. I have been watching my mother disappear into dementia over the last four years.

Ms Close, who was also the environment minister, denied her resignation was tied to the algal bloom devastating the state's coastline.

"Ironically, it made me hesitate because I was concerned that people might think that there was a connection between the two and that I was somehow fleeing the algal bloom, which is not the case at all," she said.

"I would wish the algal bloom away if I could, but there have been some things that have come out of it that I think are important — to understand the true impact of climate change is here now. It's not in the future. It's here now."

When asked about her role as one of the top female politicians in the state, Ms Close said: "I'm looking forward to the day when it isn't a legacy you have to consciously identify as a woman passing to a woman."

"We are still there and I am pleased occasionally women will stop me in the street and say that I mean something to them," she said.

'The job's never done'

Mr Mullighan said his "beautiful family" was at the forefront of his mind when making his decision to resign.

"I didn't feel I had another four years of committing this much time and effort to these roles to the exclusion of the time that I can show at home as a husband and as a father," he said.

He said he had "lost both my parents" and his wife Antonia had "lost her father".

"It takes a a village to raise children, and our village is a little bit smaller than most," he said.

"So I want to make sure while the kids are still young and I'm relatively young, that I can be around more and be more present as a husband and a father," he said.

Mr Mullighan said he was "tremendously lucky" to work as an MP and serve his local community and that the job came with "an enormous amount of dedication and sacrifice".

"I mean, you always leave these jobs with regret, if for no other reason because the job's never done, either as a local MP or or as a minister," he said.

He said he has not turned his mind "to what's next" in his career.

Mr Malinauskas said new ministers will be sworn in in the coming days.

Flinders University politics expert Rob Manwaring said the departure of two senior figures would mean a "fairly significant" reshuffle in the cabinet.

He said it would be interesting to see how the gender and factional balance take shape in the reshuffle of the cabinet.

"So whilst overall the gender balance within the cabinet is pretty strong … there is a dearth of women in those senior roles within cabinet," he said.

"Susan Close comes from the left faction, Mulligan from the right faction, and there will be sort of a like-for-like in terms of replacement to ensure an overall kind of fractional balance and generally the Labor Party has handled that relatively well."