The Civil Aviation Safety Authority is warning anyone caught flying unapproved drones over fire affected areas in New South Wales could be fined.

It says there have been two incidents in the past week of people operating drones over fires in Lithgow and the Blue Mountains.

CASA says the drone flights are putting firefighting responses at risk.

Footage of a remotely piloted drone being operated in the area of the State Mine fire near Lithgow, as firefighters battled to control the blaze, was posted on YouTube on Monday.

The footage shows the drone being flown above firefighters and the nearby fire as well as into a burnt-out building.

CASA has seen the footage and says it appears to have breached Civic Aviation Safety Regulations.

Key points: CASA warns against unauthorised drone flights in fire-affected areas.

CASA warns against unauthorised drone flights in fire-affected areas. Fires continue to burn uncontrolled in the Blue Mountains.

Fires continue to burn uncontrolled in the Blue Mountains. ABC Emergency: abc.net.au/news/emergency

ABC Emergency: abc.net.au/news/emergency Rural Fire Service: rfs.nsw.gov.au

Rural Fire Service: rfs.nsw.gov.au Bureau of Meteorology: bom.gov.au

It says flying a remotely piloted aircraft in the same airspace as helicopters and planes fighting fires "creates a real risk of a mid-air collision".

The authority's director of aviation safety, John McCormick, says the unapproved use of remotely piloted aircraft during a bushfire was irresponsible.

"People who have a 'drone' must fly according to the Civil Aviation Regulations and they must use their common sense," he said.

"Flying an unapproved remotely piloted aircraft near firefighting aircraft, firefighters and firefighting vehicles is dangerous."

Civil Aviation Safety Regulations state remotely piloted aircraft must be kept 30 metres from people unless otherwise approved.

CASA says it is also an offence to operate a remotely piloted aircraft in controlled or restricted airspace without approval or to operate in a way that creates a hazard to another aircraft, person or property.

CASA spokesman Peter Gibson says the drones could force air crews to land.

A firefighting helicopter flies over the bushfire near Lithgow. ( Prime News: Phoebe Moore )

"If they stop for half an hour or an hour, the bushfire will continue to burn and could put properties and lives at extra risk," he said.

"If we get evidence of drones being used in an unsafe manner, we certainly will issue fines and... the fines can be many thousands of dollars."

A watch-and-act alert remains in place for the State Mine fire, which is burning in the area around the Bells Line of Road.

The Rural Fire Service said crews would continue with back-burning operations north of Mountain Lagoon into Sunday.

Emergency services and Government officials briefed hundreds of fire-affected residents about the recovery effort at a community meeting in Winmalee on Friday night.