Pre-election leaders' debates can be uneventful affairs, with a lot of unstimulating talk about stimulus measures and bickering between the candidates.

And while today's public tete a tete in South Australia was no love fest, it reached its climax when Liberal leader Steven Marshall and SA Best's Nick Xenophon were asked about Canberra's so-called 'bonk ban'.

Yesterday, Prime Minister Malcolm Turnbull announced ministers would be banned from having sexual relationships with staffers under a rethink of the ministerial code of conduct.

The announcement was in response to Deputy Prime Minister Barnaby Joyce's affair with his former media adviser, Vikki Campion.

At today's debate, hosted by the Property Council, mediator and Advertiser columnist Tory Shepherd concluded by asking both Mr Marshall and Mr Xenophon whether they would consider introducing a similar ban on SA ministers.

"Would either of you want to ban the bonk in South Australia?" she asked.

The response elicited a smirk from the candidates.

"I don't think we're going to have a ministerial bonking-led recovery in South Australia," Mr Marshall said.

Soon after, the Liberal leader added: "There's no boozy, bonky culture in the Liberal Party. We're just hard at it everyday, and I mean work! We're hard at work every day."

Mr Xenophon, whose seven-year relationship with former staffer Jenny Low (who was in attendance at the debate) recently generated headlines, was more straight-faced when giving his answer.

"It's a matter for consenting adults," he said.

"I think it crosses over into the public sphere — it's when taxpayer funds have been involved."

Premier Jay Weatherill was not in attendance to provide his views on the matter.

He shunned the debate, in retaliation for the Property Council's opposition to the State Government's failed bank tax.