The man Adam Giles rolled as chief minister has announced he is re-entering politics and has quit the Country Liberals (CLP), the party he once led.

Terry Mills, chief minister from 2012 until he was replaced by Mr Giles in a coup the following year, will stand at this month's election as an independent in the seat of Blain.

Mr Mills held the seat from 1999 until 2014, when he quit politics.

At a press conference on Sunday, Mr Mills likened the current state of governing in the Northern Territory as a car crash.

"At the scene of an accident, one has a moral obligation to render assistance," he said.

He said the decision to leave the party he led back to power and stand as an independent had "weighed on my heart deeply" and that events of the last four weeks had "turned my head".

The picture of a laughing Terry Mills, which the man himself retweeted soon after news of Adam Giles being rolled, which turned out to be premature. ( Supplied: Twitter )

"I thought I'd made my contribution but now I am required to act ... rather than just be disappointed and comment from the side," he said.

Mr Mills said he realised his actions would have "massive implications" for the CLP, but was "compelled to respond and come back".

He dismissed suggestions he may rejoin the CLP in the future and said he was unconcerned over the damage done to the party's image by his defection.

"I am not particularly interested in the reputation of the CLP, I am concerned for the reputation of the Northern Territory," he said.

Mr Mills said his actions were driven by a need to act to prevent Labor taking power and described the NT as being seen from afar as a "laughing stock".

He said it was a "complete falsehood" for anyone to compare him to former party leaders who had embarked on a campaign of destabilising their new leader.

"I am one who has remained silent, I have not been involved in any activities, I have not undermined or leaked," he said.

Mr Mills said he had looked to dumped former Labor prime ministers Julia Gillard and Kevin Rudd as to "what not to do" after being rolled as leader.

Later in the day, Mr Giles fronted the media and said he welcomed Mr Mills into the election race.

"It's a free democracy ... I wish him all the best," Mr Giles said.

The CLP candidate in the seat of Blain is Marie-Clare Boothby, a financial services provider.

Bad blood began after coup

The announcement is the latest development in the long-running saga of ill feeling between the men, which began after Mr Mills was ousted by Mr Giles while on a trade mission to Japan in 2013.

Terry Mills has quit the CLP and slammed Adam Giles. ( Twitter )

Mr Mills announced his retirement from politics in 2014, forcing a by-election in his seat of Blain, which was won by Nathan Barrett.

The resentment deepened in 2015 when Mr Mills was sacked from his role as the Territory Government's Commissioner to Indonesia and ASEAN after retweeting a photo of himself laughing during the attempt to oust Mr Giles as chief minister, which ultimately failed.

Mr Mills was scathing of how he was treated by Mr Giles, stating at the time: "To be effectively politically assassinated whilst I was in Tokyo and now, in my view, politically assassinated whilst in Jakarta looks like overkill to me but it certainly plays out quite badly."

"The optics of this aren't so good."

The development of Mr Mills re-entering politics is the latest event in a tumultuous term of government for the CLP.

Mr Mills joins other former CLP members of the Cabinet Kezia Purick and Robyn Lambley who have heavily criticised Mr Giles and the culture within the party.