A former volunteer firefighter in North Canterbury thinks he has a good shot at winning an unfair dismissal case against the Fire Service.

Kaiapoi's Brent Cairns was discharged from the brigade in April last year, after five complaints, the main one being that he used a firetruck to water a new food forest as part of a community event.

Since launching legal action, he said he' also been asked to provide advice to other people considering taking the Fire Service to court.

"One of the examples, one of the volunteer firefighters who had served 15 years as a volunteer, was discharged for defriending five people on Facebook."

He filed papers in March, and said he's now received the Fire Service's statement of defence.

"They reckon they don't have to comply with the Bill of Rights in all sorts of things. From people that have viewed the defence, it's pretty weak. So we're looking forward to getting in front of a judge to get some form of remedy ."

The Fire Service said Cairns’ concerns have been the subject of a number of investigations, including some conducted by external and independent barristers.

Cairns said the way permanent managers laud their power over volunteers is leading to hundreds of them leaving the force every year.