NSW volunteer firefighters have used Facebook to raise money to buy their own face masks, but the NSW Rural Fire Service (RFS) said crews should have all the equipment they need.

Key points: Volunteer firefighters have raised money through a fundraising campaign to buy face masks

Volunteer firefighters have raised money through a fundraising campaign to buy face masks The NSW RFS said that all masks issued to firefighters are "certified and tested rigorously"

The NSW RFS said that all masks issued to firefighters are "certified and tested rigorously" The RFS urged crews to raise concerns with their district

Copacabana on the NSW Central Coast and Ingleside in Sydney's north are among several brigades that have started grassroots campaigns appealing for funds to buy more face masks.

The Central Coast RFS crew said they're "horrified" they have had to use RFS-issued P2-grade dust masks which they claim do not offer sufficient protection.

Copacabana Rural Fire Brigade treasurer Joe Arena wrote on Facebook that they were fundraising to buy eight masks.

He said the crew was "completely exhausted" from battling the "mega-fire" blazing in the Hawkesbury and Central Coast over the past two weeks.

"In defence of the RFS, these are unprecedented conditions on a scale no one could have anticipated," he wrote.

"But we have no choice but to go out and fight fire with what we have."

The Ingleside campaign argued they have "nothing but a P2 dust mask to protect their lungs when standing right next to the fires".

It costs $135 to fit out each firefighter with a professional-quality respirator, and there are ongoing costs associated with certification.

But the RFS said P2 masks are currently the safest method of protection and that P3 masks could even make breathing more difficult while fighting fires.

The RFS said P2 masks are "certified and tested rigorously".

An RFS spokesman said crews should raise their concerns with their district if they feel they do not have adequate supplies.

Firefighters at work on the Currowan fire between Batemans Bay and Ulladulla. ( AAP: Dean Lewins )

"NSW RFS firefighters are provided all necessary tools and equipment to undertake their work. This includes all personal protective equipment, fire appliances and associated hoses, nozzles, etc," the spokesman said.

Within hours of the fundraising campaign, the Central Coast crew received enough money to buy respirators for themselves and neighbouring brigades.

Volunteer Fire Fighters Association president Mick Holton said RFS members are issued with standard P2 masks but he said the RFS "could do better" as many volunteers were buying their own masks equivalent to a P3.

"It's probably high time the government started to look at how we can provide some better respiratory protection," he said. "It shouldn't come out of a volunteer's pocket."

The RFS said it would take a long time to change safety equipment protocols.

"For the service to consider changing any of its provided firefighting equipment and apparel would require a full and compressive scientific research and evaluation process," it said.