The Northern Territory government is in turmoil with three ministers sacked over their criticism of budget management and leadership.

The chief minister, Michael Gunner, has given the boot to the resources and Aboriginal affairs minister, Ken Vowles, as well as assistant ministers Jeff Collins and Scott McConnell.

Gunner said in a statement on Friday the three MPs had “broken caucus rules and standards” to which they signed at the start of the government’s term.

As well, Vowles had been expelled from cabinet for “breaking cabinet confidentiality”, Gunner said.

“Territorians expect and deserve government to be solely focused on their concerns and making their lives better,” he said.

The trio are expected to sit as independents in the NT assembly.

Vowles said Gunner, who is in New Zealand on holidays, had informed him of the decision over the phone.

“Michael Gunner called me and he said, ‘You’ve broken caucus rules and you no longer have a position in cabinet and I’m banning you from the caucus’,” Vowles told reporters in Darwin on Friday.

Vowles said he wanted to continue as a Labor MP, but admitted it was a decision for the party.

“I feel for Jeff, I feel for Scott. We will consider what we are doing later but I hope we stay within the Labor party.”

He said there was strong support in the Labor caucus for a leadership change and many caucus members supported him for the top job.

Vowles said the Gunner government was now focused on “spin” and not addressing key issues such as crime and proper budget management.

“What we need is a chief minister who is going to make the hard decisions for the territory,” he said.

The NT News on Wednesday published a leaked email in which Vowles likened the government to a business that was “trading insolvent”.

“Our commitments need to be revisited, our public service growth must stop, a real freeze on new positions, the business (class) trips, the chartered flights and spending needs to stop,” Vowles wrote.

“We need to re-evaluate every announcement, every commitment because we need to make the hard decisions for the future of the Territory, not decisions to enhance our re-election prospects.”

On Friday, the treasurer, Nicole Manison, described Vowles’ comments as “unhelpful” and said she had spoken with her colleague.

Collins told ABC radio in Darwin on Friday there was “no diversity of conversation” in the Labor caucus.

The federal resources minister, Matt Canavan, a Nationals senator, said he was sad to see his NT colleague axed.

“Sorry to see @KenVowles removal from NT cabinet. Always found him a straight shooter and good to work with. So much promise in NT. Let’s hope things can get back on track,” Canavan tweeted.