Greens kick-off SA campaign with lattes

With a piccolo latte in hand, Greens leader Richard Di Natale began his South Australian campaign at a produce market.

He met voters at the Adelaide Central Market on Tuesday with Senator Sarah Hanson-Young, who secured top spot on the party's SA senate ticket, and Senator Robert Simms, who will rely on preferences to retain his job.

The trio sipped coffee, nibbled on cheese and met with an organic food stall holder.

"Don't go munching on any onions Richard," Senator Simms quipped.

He'll compete with the Nick Xenophon Team to save his spot but said the fight would likely come down to him and Family First Senator Bob Day.

"The choice couldn't be starker," Senator Simms told reporters.

"You've got the homophobia and the sexism of the Family First party versus the forward-looking agenda of the Greens."

Senator Di Natale said having Senator Simms re-elected could make the difference in getting through strong climate laws and action on clean energy investment.

He also said the minor party was open to policy negotiations with Labor if there was a close result or a hung parliament "if it means we get some progress of the key issues that matter to us".

But Senator Di Natale brushed off reports that the Greens were negotiating a preference deal to end Labor's stranglehold on the Melbourne seat of Batman.

"The Greens won't be preferencing the Liberals in any seat in Australia," he said.