Incoming Greens leader Richard Di Natale has addressed rumours he organised his ascent to the position ahead of time.

The senator said he spoke to his wife Lucy about the possibility of taking the leadership “six months ago”.

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“Here’s a newsflash. We’re a year and a half away from an election and there’s a chance that the leader might step down. I was talking to Lucy about this six months ago,” Mr Di Natale said at a joint press conference with outgoing leader Christine Milne on Wednesday.

“I’m smart enough to know when something could happen, so we had a chat, we had a chat. I would not be doing this if I didn’t have her full support.”

The Greens elected Mr Di Natale as leader just after noon on Wednesday.

The former GP and Victorian Senator was elected unopposed after Ms Milne shocked the party with her resignation on Wednesday morning.

Ms Milne took to Twitter to reveal she would not be running in the 2016 election.

Fending off a question implying the move was crafted to prevent Melbourne MP Adam Bandt and South Australian Senator Sarah Hanson-Young from leading the party, Ms Milne declined to answer.

“I’m not going to talk about the last three years in terms of the discussions we have had,” she said.

Senators Scott Ludlam and Larissa Waters were elected as co-deputy leaders, rounding out the leadership team of the 11-member party.

The unusual leadership structure is not unique, as the New Zealand Greens have long had a co-leadership arrangement.

insert many jokes about co-deputies. The NZ greens have managed co-leadership for ages. Good on em.

— Nicola Paris (@peacenicsta) May 6, 2015

Public Policy Fellow at Melbourne University Nicholas Reece said the greens spill was “coordinated” to push former deputy Adam Bandt out of leadership and keep South Australian Senator Sarah Hanson-Young from being elected.

“The way in which Christine Milne and Richard Di Natale coordinated their social media suggests there was a coordinated campaign to switch from Milne to Di Natale and to rebuff the leadership aspirations of Adam Bandt and Sarah Hanson Young,” Mr Reece told The New Daily.

Mr Bandt took to Twitter to say he was “happy” to lose his deputy position and become a backbencher.

“Congrats Richard & new team! V happy to hand over Deputy to focus on new baby (due in few wks!) & winning further Reps seats in Vic & NSW,” he said.

Mr Di Natale outlined his two core agenda items, health and the environment.

After taking the reigns from Ms Milne Mr Di Natale said his party would “get things done”.

He foreshadowed “taking tough action on climate change”.

“If we don’t get climate change on track in this country then everything else is redundant, isn’t it?” he said.