Electoral commissioner Mick Sherry has found a claim made by Opposition Leader Steven Marshall that the Liberal's energy policy would save SA households more than $300 is misleading, as many of the savings would occur regardless.

Federal Labor Senator Alex Gallacher was also "inaccurate and misleading" when he claimed in a flyer that "the Libs have a secret plan to cut $557 million of the GST share from South Australia", the commissioner found.

In separate letters to the Liberal and Labor camps, who levelled complaints that led to the findings, Mr Sherry said he had asked each party to publish retractions.

That call was heeded by Mr Gallacher on Wednesday.

"The statement was inaccurate and misleading to a material extent, and I now retract it," he said in a statement.

Premier Jay Weatherill said Mr Gallacher's flyer had "nothing to do" with his team.

"It was a mistake. He didn't publish it any further as soon as it was drawn to his attention," Mr Weatherill told reporters on Wednesday.

Mr Weatherill said the real issue was with Mr Marshall's energy savings claim, which he first made in October, given his ambition to become SA's premier.

"He has been misleading, he has been incompetent and South Australians can not afford to risk their future on Steven Marshall," he said.

"Absolutely it is a hanging offence."

Mr Marshall has not yet issued a public retraction, but SA-BEST leader Nick Xenophon said he was expecting him to do so.

"If he made claims that were unsubstantiated he needs to correct those claims and he needs to do it ASAP," Mr Xenophon told reporters.

Mr Xenophon did not escape a slap on the wrist from the electoral commission, which said he had breached the Electoral Act for having too much advertising on a Fiat Bambino campaign car.

The SA-BEST leader said he thought parts of the Act may be in breach of the constitution and that the car won't be stood down before Saturday's election.

"The Fiat Bambino will be around right until the close of polling," he said.