Firefighters from the Mid and West Wales Service say they have growing concerns for public safety.
It comes just a week after the Fire Brigades Union spoke of its worry about plans to replace some traditional fire engines with smaller vans.
The Chief Fire Officer of the service says the vans will improve firefighting capabilities, but the union disagrees with this.
Much of the service is now manned by so-called 'retained' fire crews.
These are not based at a station, but travel there from home or work to respond to an emergency.
Some full-time firefighters argue that though this saves money, it adds time and puts lives at risk.
However, the Chief Fire Officer of the service says levels of emergency response have not changed.
But some firefighters say that the public's idea of the service is very different to theirs.
In Pontardawe firefighters claim that a change to working practices is potentially tiring and dangerous.
But the Chief Fire Officer argues that the traditional fire service model is actually based on a retained firefighter system and that those firefighters employed on a wholetime contract work a 42 hour week. Their conditions of service are negotiated nationally and comply with the law.