Prime Minister Malcolm Turnbull has thrown his support behind South Australian Opposition Leader Steven Marshall ahead of next week's state election.
Mr Turnbull called for an end to the "failed leadership" of the the Labor government during a visit to the McLaren Vale wine region on Saturday.
"How can you be in a position where you have the most expensive and the least reliable energy in Australia?" he asked reporters.
"The long and sorry era of Labor government in this state has let South Australians down."