Whanganui firefighter support units can no longer attend emergencies with lights and sirens going.
Fire chief Bernie Rush told the support crew earlier in the week they must respond to callouts at road speed - no speeding to jobs or cutting through intersections.
The unit's duties including controlling traffic, taking care of the other firefighters, and acting as a scene guard at some suspicious fires.
"Whanganui is quite unique in that our support unit has always used lights and sirens," Mr Rush said.
According to national fire service policy, support units are supposed to attend all incidents at road speed, but Whanganui's one had not been made to do so until recently.
A couple of support unit crashes in other parts of the country drew Mr Rush's attention to the issue, and he decided to crack down on it and enforce policy locally.
"Their main role is scene safety. They're not, strictly speaking, there for an urgent emergency response, they're there for a support role."