SA Liberals in pre-election reshuffle

South Australian opposition leader Steven Marshall has reshuffled his front bench, dropping two long-serving MPs in favour of youth.

Steven Griffiths and Duncan McFetridge have lost their spots and have been replaced by Stephan Knoll and David Speirs.

Mr Knoll has been made opposition police and correctional services spokesman and Mr Speirs the Liberal environment and climate change spokesman.

The changes come just over a year out from the next state election.

Mr Marshall says his new team reflects the group he will take into government if the opposition wins office in March 2018.

"A Liberal government will be geared to meet the greatest single challenge South Australia faces - to reverse the decline in our economy and re-build belief and confidence in our state," he said.

"I am looking forward to the enthusiasm and new ideas that David and Stephan will bring to the shadow cabinet."

Among other changes Rachel Sanderson will take on the child protection portfolio while Dan van Holst Pellekaan will be focus on energy and mining.

Tim Whetstone will be the opposition spokesman on investment and trade.

Vickie Chapman remains deputy leader and while Rob Lucas has retained the treasury portfolio.