UPDATED: Former chief minister Michael Gunner has resigned from Parliament, two months after his shock resignation as chief minister, sparking a by-election in the electorate of Fannie Bay.

Mr Gunner made the announcement during an adjournment speech on Wednesday night in Parliament, as he had been expected to do earlier in the day, saying that the decision to resign as the Member for Fannie Bay was “harder than stepping away as chief”.

“It’s what’s best for the people I serve and what is best for my family.

“I will miss this place, my fellow members, my friends,” he said, adding that “the Territory is in safe hands” with current Chief Minister Natasha Fyles.

“I will work again,” he said. “I’m not in a position to retire for life. I have no plans yet and I can’t see myself working again until late this year at the earliest, but my priorities are clear: my family comes first, supporting my wife and raising my boys.”

He added that he will remain in the Territory, despite wide speculation he had been spending significant time in Queensland over the last two months.

“I’m not moving anywhere, this is my home where I was born and my boys were born. This is where they will be raised,” he said.

“There is no better place to grow up. I say goodbye to Territory politics, but I am Territory for life.”

Mr Gunner resigned as chief minister in May, citing family reasons, but vowed at the time to stay on to represent his constituents.

“My head and my heart are no longer here, they are at home,” he said at the time, but remained in the role of MLA for more than two months.

His resignation from politics will spark a byelection in the electorate of Fannie Bay.

Speculation had started earlier this week that Mr Gunner would be resigning from politics.

It’s understood the announcement had caught the Opposition CLP off-guard, who do not have a candidate selected to run in Fannie Bay.

The party is still reeling from an embarrassing by-election defeat in Daly last September that saw a deeply unpopular Gunner Labor Government gain the seat from the CLP, marking the first time an incumbent government won a seat from an opposition.

A date for the by-election has not been determined.

Back in Parliament on Wednesday night, Labor members took turns paying tribute to Mr Gunner.

Chief Minister Natasha Fyles said he had “given enormously to our community”.

“You certainly gave me enormous support and the confidence and backed us in to make decisions and it wasn’t easy,” she said.

“And I know on you it was particularly personally tough … I thank you for your commitment on behalf of Territorians for always putting the Territory – and particularly the advocacy for the people of Fannie Bay, Ludmilla, Parap, and the Gardens [first].”

Deputy Chief Minister Nicole Manison, who was Mr Gunner’s deputy as well, said Mr Gunner was the most “transformative” chief minister the NT has ever had.

“He has truly changed the NT for the better,” she said, adding that he was “the person we needed as chief minister” and a “smart bloke, big thinker,” who “encompassed Labor values”.

First elected in 2008, became chief minister on pledge to restore integrity in 2016

Mr Gunner was first elected to Parliament in 2008, replacing Clare Martin in the seat of Fannie Bay after she retired. He was elected chief minister in August 2016 on a campaign to restore integrity to politics after four years of a disastrous and scandal-plagued CLP government.

However, Mr Gunner oversaw a scandal-plagued government of his own, including a corruption report by the ICAC last year that found his chief of staff engaged in misconduct to see a $12 million grant awarded to the Darwin Turf Club for a grandstand project. It was later revealed that Mr Gunner had taken the flawed grant submission into Cabinet under the arm and argued for it to be approved.

It was also revealed after his resignation as chief minister that he is currently under investigation by the ICAC for alleged travel rorts involving the use of taxpayer money to campaign in remote communities ahead of the 2020 NT general election.

There have also been unresolved questions about his knowledge of the details of the so-called Labor cocaine sex scandal involving an MLA and a senior staffer and whether he took action when he first learned of it, or allowed his staff to help cover it up.

The ICAC is also currently investigating allegations of political interference between Mr Gunner and the Police Commissioner in the decision to charge Constable Zach Rolfe with murder for the 2019 shooting death of Yuendumu man Kumajayi Walker during a failed arrest.

Mr Gunner’s resignation as chief minister was followed by head public servant Jodie Ryan who resigned from the highest public service office days later.