Senior Labor MP Tom Koutsantonis has been reappointed Treasurer of South Australia following a sweeping reshuffle of Premier Peter Malinauskas’ cabinet.

Koutsantonis, who last held the Treasury portfolio between 2014 and 2018, had been serving as Minister for Transport, Infrastructure, Energy and Mining since Labor’s 2022 election victory.

He will relinquish transport and infrastructure, with former Sport Minister Emily Bourke stepping into those roles.

The changes come after the sudden resignations of Deputy Premier Susan Close and Treasurer Stephen Mullighan from cabinet on Thursday.

Koutsantonis and new Deputy Premier Kyam Maher were formally sworn in this morning at Government House.

Labor MPs Lucy Hood and Rhiannon Pearce have also joined the frontbench. Hood, the member for Adelaide, has taken over Dr Close’s former environment portfolio amid the state’s ongoing algal bloom crisis.

The crisis has devastated marine life and led to residents in coastal regions reporting flu-like symptoms since it was detected in March.

Pearce, representing King, has been handed recreation, sport and racing, along with emergency services and corrections.

Education Minister Blair Boyer will assume responsibility for the police portfolio, while Premier Malinauskas has added defence and space industries to his own ministerial load.

Malinauskas said the reshuffle brought “significant new talent and fresh ideas to the front bench, balanced with stability, experience, continuity and strength of leadership”.

“I am proud of the fact that for the first time in history we have more women than men in Cabinet,” he said.

Opposition deputy leader Josh Teague said the government was “seemingly entirely preoccupied with a crisis management announcement … and then appeared to pat itself on the back at its capacity to spin this crisis at the top levels of government”.

“Meanwhile, the substantial day-to-day tasks of the work of government have gone very much neglected this week, and that’s particularly true of the state’s coastal ecological disaster, the ongoing harmful algal bloom,” he said.

“The government’s response to the algal bloom crisis has been flat-footed from the very beginning and the premier has just hospital-passed this bungle to a first-time minister.”

With AAP