ACT Fire and Rescue chief officer Paul Swain lodged a bullying complaint against his own boss, Emergency Services Commissioner Dominic Lane, in the middle of this year.

The allegations were formally investigated and found to be unsubstantiated in an independent process which was subsequently reviewed by WorkSafe ACT.

But the fact Mr Swain even made the formal complaint, regardless of its veracity, has raised concerns that a seemingly fractious relationship existed between two of the ACT's most critical emergency services officers.

Mr Swain quit the agency early this month, leaving Canberra's urban firefighters without a permanent chief officer at the start of summer.

He still had roughly six months to serve in his current term, which was due to end in late May.

An Emergency Services Agency spokesman said Mr Swain left his job for "personal reasons". The former fire chief could not be reached for comment on Sunday.

The government refused to discuss the terms of Mr Swain's departure, including how much leave the chief officer had taken in the months leading up to his resignation, or whether he received any additional payment.

But a spokesman said the ACT's emergency services remained fully prepared for the fire season.

"ESA personnel stand ready and able to meet the challenges of what is expected to be a demanding fire season."

Deputy chief officer Conrad Barr is currently acting in Mr Swain's vacant position.

Mr Swain is understood to have lodged the complaint against Mr Lane in July, and left on December 3.

ACT Opposition Leader Jeremy Hanson said the government had repeatedly failed to deal with cultural problems in the ESA.

Mr Hanson said former Emergency Services Minister Simon Corbell had left issues unresolved, instead passing the buck to his replacement Joy Burch.

"Allegations of a toxic culture and claims of bullying headline a string of issues under ACT Labor's management of emergency services," Mr Hanson said.

"It's clear, like we've seen with the health system, that ACT Labor has a management problem."

Ms Burch, who was announced as the new minister this month, responded that she would not be drawn into attacking ESA staff, who she said had the "community's wellbeing at their core".

"A complaint was made, it was independently reviewed and the complaint was not substantiated," she said.

"The ACT government does not intend to follow the Canberra Liberals' pattern of besmirching individual reputations in their attempts to score political points by speculating publicly about an unsubstantiated complaint."

The minister is due to tour the ESA headquarters in Fairbairn on Monday, before travelling to a fire station in Forrest to hand over the keys to two new fire pumpers.

The United Firefighters Union expressed disappointment at Mr Swain's departure.

"Our members are concerned about the unknown, about the future," ACT branch secretary David Livingstone said.

"We're not sure who is going to be the chief come next fire season."

"But regardless of who ends up in the chief officer's position, firefighters will still jump on trucks, attend fires and motor vehicle accidents, and do our jobs."

Mr Livingstone said Mr Swain was one of the few leaders in ACT government who was able to maintain a good relationship with the union.

"That's because the objective that we were always trying to achieve was the same, which was a safer community for Canberra," he said.

Mr Swain began his current term in May 2010.

His departure comes at a time of considerable change for ACT Fire and Rescue.

An expenditure review is currently being conducted to try and glean savings from the ESA, and the government's major program of upgrading and relocating fire and ambulance stations is still ongoing.