During large, out-of-control bushfires in Australia firefighters rely on water-bombing helicopters which will have to be grounded if a drone is spotted nearby, authorities say.

With recreational drone ownership exploding into the thousands over the past year, air safety regulators and the nation's aerial firefighters fear drones are a very real threat to safety, and they warned amateur operators to stay well away.

Superintendent Anthony Ferguson from the New South Wales Rural Fire Service's (RFS) State Air Desk said firefighting pilots nationwide were concerned.

"They're just trying to fly safely in what are very high stress situations and you add in this other element and it becomes incredibly dangerous for them," he said.

Even during a raging bushfire, helicopters would be grounded.

"If you take those aircraft out of there you're losing situational awareness from above, you're losing the capacity to be able to reach fire that firefighters won't be able to reach from their tankers, and you're losing a vital support mechanism," Superintendent Ferguson said.

Unlike birds that hit choppers, a drone is solid and could do enough damage to bring an aircraft down, according to Civil Aviation Safety Authority (CASA) spokesman Peter Gibson.

"It's almost impossible for a fire-fighting pilot to see a drone in the air, particularly in a bushfire situation when you may have low visibility and high winds and they're concentrating on doing their job fighting the bushfire," he said.

"They're doing [their job] in a very planned, organised mission and then to have a random flying object nearby just creates all sorts of unnecessary risks."

No law prevents drones flying near bushfires

Current regulations are that drones have to be 30 metres away from people, they are not be used in built-up areas, not to exceed 400 feet in height and not be flown in controlled air space, but there is no law against flying near bushfires.

Drones must not create a hazard for other aircraft, but if the device was several hundred metres away from its operator, how would they know if a firefighting aircraft was approaching?

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Superintendent Ferguson said the nation's aerial firefighters have sent a submission to CASA calling for the law to be amended to include a three to five nautical mile exclusion zone around a bushfire.

CASA is considering that submission.

"We've received all those comments, we're still looking at those," Mr Gibson said.

"A number of changes are being considered there, they haven't been brought in yet, but we are looking all the time to make sure the rules covering remotely piloted aircraft and recreational drones stay up to date with this growing sector of aviation."

Drone ownership 'exploding' in Australia

Two years ago drones were not a problem for aerial firefighters, but now ownership of the remotely-controlled aircraft is "exploding" according to CASA and the NSW RFS.

"You see a lot of people trying to get that wonderful moment [using a video camera attached to the drone] that they can put on Facebook or on YouTube, they're not thinking about the full-on effect of what they're doing," Superintendent Ferguson said.

"We've had one fire season where we saw four serious incursions and now this year I'm very nervous about what we're going to face again."

Enforcing regulations for drones was a challenge as they became more popular.

"No-one knows exactly how many recreational drones are out there but you would have to assume there are tens-of-thousands," Mr Gibson said.

"Certainly the Civil Aviation Safety Authority has printed around 100,000 flyers to give to retailers that contain the rules so we believe many are being sold all the time."

UAV expert Brad Mason (L) demonstrates how to use a drone in Brisbane. ( ABC )

Industry group Australian Certified UAV Operators (ACUO) said the number of licensed users in Australia was 105 in May and that number was expected to be 200 by Christmas.

The group said certified operators who hold drone pilot licences abide by the rules, but it was recreational operators who do not have licences that were causing concern.

"Most people are just keen to get it in the air and get some pictures and have a play with it," ACUO secretary Brad Mason said.

"There are dozens of videos on the internet of people flying their drone as high as possible and then watching it plummeting to the ground.

"That's just stupidity as far as we're concerned, the regulations are there, they're quite clear.

"I don't know if we can be any clearer than that and it's just that people have to learn to abide by the regulations."

A drone is very easy to operate, even children can do it.

In the time it takes you to open the box and charge the battery - about an hour - you could learn all you need to know to be airborne.

"It's good that it's not so difficult to be able to fly these things anymore," Mr Mason said.

"But on the same token because it's so easy, it's very attractive for people to go out and do it."