The two tankers and eight firefighters were pulled from duty at Kurri Kurri and Bellbird stations in the Hunter region from 5am until midday on Friday, despite both areas being on red alert for bushfires, the Fire Brigade Employees Union says.

It is taking action in the NSW Industrial Relations Commission (IRC) to force the state government to comply with a ruling that no trucks be stood down during total fire bans or bushfire emergencies. A directive issued in 2008 demands that all stations and tankers be fully staffed and available on total fire ban days.

Firefighters from Kurri Kurri were part of an effort that helped save 30 houses on January 2. Bellbird fire station, south of Cessnock, is surrounded by state forest.

The union said the savings from standing down two tankers with four crew each would have been about $850.

Fire and Rescue NSW denied the trucks and firefighters were stood down as it would be against the law.

‘‘ All FRNSW fire stations and trucks were available to respond to emergencies, including those at Kurri Kurri and Bellbird,’’ a spokeswoman said.

‘‘ In fact, at Kurri Kurri Fire Station in addition to the on-call crew, an additional crew and fire truck from Carrington was standing by to bolster resources in the region.’’

FBEU president Darin Sullivan said the union had spoken to the firefighters and would present evidence to the IRC. ‘‘ What happened was not only illegal, it was dangerous. That is what we are concerned about,’’ Mr Sullivan said.

‘‘ Imagine penny pinching to save a few dollars by standing down tankers right in the middle of a bushfire emergency?’’

Deputy Opposition Leader Linda Burney said the O’Farrell government was warned this summer would be a horror bushfire season and said it was ‘‘ literally playing with fire’’.

But a spokeswoman for Fire and Rescue NSW said the union’s claims were ‘‘ completely untrue’’.

She accused the union of relying on incomplete data from the online staffing system that gave the impression some trucks were unstaffed.

‘‘ There is absolutely no substance to the claims,’’ she said.