The new SA Premier has used his first press conference to sack four senior public servants.

South Australian Premier Steven Marshall has called his first news conference at the State Administration Centre in Adelaide to announce four senior public servants have been sacked.

The new Liberal administration has sacked Department of Premier and Cabinet chief executive Don Russell, Michael Deegan from the Department of Planning, Transport and Infrastructure, Sandy Pitcher from Environment and Natural Resources and Ingrid Haythorpe from the Attorney-General's Department.

The decision will cost taxpayers about $2 million.

“I think this is an extraordinary sum but the reality is that was the detail that was contained within the contracts that the chief executives had entered into with the previous Labor government,” Premier Steven Marshall he said.

Mr Marshall said the new Government needed to implement a reform agenda, but that other department heads were safe for now.

“We don't envisage any other terminations of chief executives in the immediate future,” he said.

“It's a new government, it's a new direction and we feel there are other people that we would like serving in these very, very significant roles.”