The number of fire trucks that respond to a fire alarm will be halved as part of a state government plan to save $2 million through more selective use of its firefighting resources.
The new plan includes sending one instead of two fire trucks to respond to automatic fire alarms because of a high proportion of false alarms.
Hospitals and nursing homes will continue to be serviced by the full complement of two fire trucks because they are deemed as high risk.
Fire Brigade Employees' Union secretary Leighton Drury said the new Premier Gladys Berejiklian needs to "heed our warnings and stop these dangerous budget cuts".
"Firefighters are not backroom," he said. "We are a frontline emergency service and the bottom line here isn't dollars, it's lives.
"The current system – where both the quickest and closest firefighters are dispatched – remains the best way to save lives and property."
NSW Fire and Rescue commissioner Greg Mullins has written to the union for fire brigade employees saying the new Risk Based Response Protocols will "improve response times and efficiency".
The so-called risk-based response protocols are estimated to save $2 million.
He said the value of leave entitlements would be frozen because the plan would reduce the use of part-time fire officers who are on call.
Leighton Drury, secretary of the Fire Brigade Employee's Union of NSW, has warned the plan threatens to reduce service delivery to the community and the safety of firefighters. He said there was an increased risk of injury if firefighters in a single truck attended a call and found a genuine fire and people trapped.
In a letter to Mr Mullins, Mr Drury said the plan increased the risk of delayed attendance and of fires becoming larger.
Mr Drury said the plan would also increase the distances travelled by firefighters responding to an emergency.
The government plan includes a proposal to use permanent crew to reduce the use of and "unnecessary" disruption to part-time crews and the number of fire trucks dispatched.
"Where a permanent crew and a retained crew are co-located, it is current practice to call both crews for all incidents," Mr Mullins said.
"In future, retained firefighters will not be called unless appropriate.
"Only those resources needed are mobilised, addressing the current issue of retained firefighters responding to low risk, single pump incidents (such as rubbish and cars alight) where permanent firefighters from the same station are already responding."
Fire and Rescue NSW Deputy Commissioner Gerry Byrne said it is consulting with the Fire Brigades Employees' Union about improving its emergency response delivery to the community.
He said the risk-based response protocols use a computer-aided dispatch system and automatic vehicle location technology to ensure the quickest and most appropriate number and types of resources are deployed to incidents "to reduce inefficient and costly over-responses to call-outs".
"Under the proposed new protocols, resources would be dispatched to an incident based on availability, recognising that [Fire and Rescue NSW's] retained (on-call) crews normally take longer to mobilise than permanent crews," Mr Byrne said.
"Retained firefighters are on-call to respond to incidents from either work or home. On most occasions they have to make their way from their primary employment, home or elsewhere to the fire station, while permanent crews are either at the fire station or mobile in the truck."
Mr Byrne said the new protocols would alter the current compulsory turn-out of all crews at fire stations where there is a mix of permanent and retained (on-call) firefighters.
"This would address issues of the "over-response" of firefighters to low-risk, single-truck incidents where a permanent crew from the same station is already responding," he said.
"While these new initiatives have potential labour cost savings, the most important impact will be in providing a faster, more efficient fire and rescue service."
