SA-Best leader Nick Xenophon has defended the decision to shield some of his new candidates from wider media scrutiny.
The party announced another batch of candidates for the March election over the weekend, but Mr Xenophon says the father and son, who will run against the premier and opposition leader, are not available for media commitments until they officially launch their campaigns.
"I think that we have to do what is best for the campaign, the candidates and for SA-Best," Mr Xenophon told ABC radio on Monday.
"They will be available through the course of the campaign."
But Deputy Opposition Leader Vickie Chapman said Mr Xenophon was effectively gagging his members and putting party interests ahead of South Australians.
"Quite frankly, this isn't good enough, and the excuse that SA-Best is a start-up party is already wearing thin," Ms Chapman said.
"Mr Xenophon has today gagged his new candidates and shielded them from media scrutiny in a clear sign that he and SA-Best are more interested in their own political fortunes than the job fortunes of South Australians."
The former senator on Monday also revealed that he is personally bankrolling some of his candidates who have been asked to stump up $20,000 to run for SA-Best.
"There is a loan for some candidates, but most people have made their own contribution, the overwhelming majority," Mr Xenophon said.
Premier Jay Weatherill said it was up to Mr Xenophon on how he picked his candidates but criticised the fact many were former Liberals.
"Nick being a former Liberal makes it easy for them to slide into his party, so Labor is facing two Liberal opponents at this election," Mr Weatherill told reporters on Monday.
"Nick has to account for the way in which he selects his candidates."
The SA-Best party has previously said it would have around 30 candidates contesting both Liberal and Labor held seats for the March 17 election.