A volunteer firefighter in Australia has been charged with deliberately lighting blazes during the nation's bushfire crisis.

Photo: AFP

Police arrested the man, 19, for seven counts of alleged arson in an area south of Sydney, New South Wales (NSW).

The fire service there described the alleged acts as the "ultimate betrayal" to crews already under immense strain.

Six people have died and more than 650 homes have been lost in bushfires which have ravaged the east coast since September.

The man is not accused over those tragedies.

The NSW Rural Fire Service calls itself the largest volunteer-based firefighting service in the world. The majority of its crews are staffed by trained volunteers.

"Over the past few weeks, we've seen firefighters going above and beyond in difficult and dangerous conditions," said Commissioner Shane Fitzsimmons on Wednesday.

"Our members will be rightly angry that the alleged actions of one individual can tarnish the reputation and hard work of so many."

Police said they had been investigating a "spate" of fires believed to have been deliberately lit in the Bega Valley in the state's south since October.

On Tuesday, officers spotted a man sitting in his car next to a river in the area. Shortly afterwards, they saw smoke and a pile of grass and trees on fire.

"Police will allege in court that the man lit the fire and left the area before returning to respond to the fire as part of his duties as a volunteer firefighter," said New South Wales Police on Wednesday.

He was arrested shortly after and was due to face a court on Wednesday.

More than 120 blazes continue to burn across the state. Officials have warned that the worst of Australia's season is still to come.

-BBC