InDaily reported in July that Parnell would not contest a third eight-year term at the March 2022 state election after 14 years in the role, citing no “real reason” apart from his desire to “give someone else a chance”.

His successor – current city area councillor and former Senator Robert Simms – was elected by party members in December to fill Parnell’s winnable seat.

At the time, Parnell – a founding member of the Greens SA and the first Green elected to parliament at the 2006 election – said he had not decided whether he would retire before his term was up, but he would be “around for many months”.

He told InDaily this week he is “still reserving the right to see out my term, but also reserving the right to go early”.

But one source told InDaily this morning that the party pioneer had flagged an early retirement, which would give “an incumbent a better chance at the election than someone coming in fresh”.

“I heard May at one stage, to give Rob Simms a chance at the role before the election,” the source said.

It comes as Simms prepares to quit his day-job as a student grievance and conduct advisor at the University of Adelaide at the end of this month to “be prepared to focus on the state election campaign”.

Simms told InDaily that the University was currently recruiting to fill his role, but he refused to say whether his decision indicated that Parnell would retire early.

“As I’ve said before, that’s a matter for him,” he said.

“For me, I’m still staying on Council at this stage and there’s no change, but I’m stepping back from my other day job.”

Parnell has also refused to outline his future intentions.

“I’m not telling you,” he said when asked if he intended to retire early.

“It’s no secret that he (Simms) was pre-selected for two purposes: one was to be our lead candidate in March of next year and the other one was that if I decided to go early, he would fill any casual vacancy that arose.

“But one thing that I think Rob would acknowledge and that the party would acknowledge is that’s entirely my call when I do that – and it’s not a call that I’m making yet.”

Parnell said he still had unfinished business in Parliament, including seeing out the passage of a Bill to legalise voluntary assisted dying in South Australia, which he has co-sponsored with Labor MLC Kyam Maher.

“I’m still moving notices of motion every week, I’ve got items coming to a vote, I’m still fully engaged in parliamentary work and I haven’t made any announcement about an early retirement,” he said.

Simms told InDaily previously that his priority in the Upper House would be to deal with “two crises: the climate crisis and growing inequality in our state”.

He said he would also focus on increasing social housing stock, improving public transport and protecting public service jobs.

His possible shift to State Parliament could prompt a second Adelaide City Council supplementary election this council term, after central ward councillor and former Deputy Lord Mayor Houssam Abiad vacated his seat earlier this year to pursue a career in Saudi Arabia.

The current council term does not end until November 2022 – eight months after the next state election.

Under current legislation, a supplementary election would be called if Simms resigned from the council before January.

However, under the proposed local government reforms still before parliament, a supplementary election would be called if he resigned before November.

Simms previously resigned prematurely from the Adelaide City Council during his first term as councillor in 2015 to fill the vacancy caused by Penny Wright’s resignation from the Senate.

He served in the Senate until his defeat at the 2016 election, before being re-elected to the Adelaide City Council in November 2018.

Public servant and former Greens adviser Yesha Joshi has been preselected for the number two position on the Greens’ Upper House ticket, behind Simms.