Prime Minister Tony Abbott's firefighting efforts are no political gimmick but a long-term commitment to serving his community, fellow Liberals say.
The prime minister joined his Davidson RFS brigade in a backburning operation near Bilpin in the Blue Mountains on Saturday night.
His involvement only became public when photographs began circulating on Twitter.
Environment Minister Greg Hunt says Mr Abbott would feel he was shirking his duty if he didn't help his mates in the NSW firefighting effort.
NSW Premier Barry O'Farrell says the prime minister leads by example and he first saw Mr Abbott fighting fires in 1994.
"This is no political gimmick as some have claimed, (this is) a long term commitment to serving his community," Mr O'Farrell told ABC's 730.
"This is a bloke who leads by example, that is happening in communities around this state."
Mr Abbott has been a member of the RFS since 2001 and has vowed to remain a volunteer despite taking the nation's top job.
Asked if the prime minister should be putting himself in harm's way, Mr Hunt said "that's just who Tony Abbott is".
"He goes off and does these things ... and he's gone off and done them quietly, by himself, without media," Mr Hunt told ABC radio.
"This is the very essence of who and what he is.
"For him he would feel ... that he was shirking his duty if he used his office to try to avoid what he regards as a blood commitment to his fellow firefighters. The men and women not just of Davidson, but of the RFS in general."
Australian Federal Police would not comment on matters of its protection operations.
But they said no additional costs were incurred by the AFP beyond the regular cost of an ordinary weekend of protection.