Police Media's Greg Lambert said the helicopter was being flown by Christian Cartigue, 40, of the central Queensland city of Rockhampton.

Also killed were 19-year-old Jessica May Cousins, and 20-year-olds Whitney Michelle Dawn Pinney and Sarah Louise Thomas. All three women were from Kununurra.

A 1km-long fire that started when the chopper exploded has now been contained by WA's Department of Environment and Conservation.

The Bellburn airstrip where the helicopter took off from remains closed, and all scenic flights in the area have been suspended.

Sergeant Lambert said rugged terrain in the remote Kimberley location was hampering recovery operations.

Ironman legend Grant Kenny who owns the chopper company, Slingair Heliwork, is travelling to the crash site.

The crash is the fourth explosion of a Kenny-owned chopper in the past decade.

Inspector Paul Zegir from Western Australia's Police Operations Centre said the chopper crashed about 1pm on Sunday, near the Kimberley-region town of Warmun.

Kununurra mourns

The CEO of Wyndham East Kimberley Shire Peter Stubbs said the death of the three young women had hit his community hard.

"It is a young community Kununurra, partly because it is a remote location and so forth," he told Radio 6PR.

"The young people were well known in the local community, that's for sure. It is a great tragedy."

The crash occurred 12 kilometres north-east of Bellburn air strip, sparking the bushfire which raged overnight.

Slingair Heliwork is WA's largest privately-owned aviation firm.

The Queensland-based Curry Kenny Aviation Group owned by Grant Kenny bought Slingair Heliwork from Kununurra-based aviator Kerry Slingsby in May 2008.

The company name carries the maiden name of Kenny's wife Lisa. The celebrity couple are former Olympians, she as a swimmer and he as a bronze medallist kayaker.

Kenny, 46, has been a keen aviator since gaining his pilot's license at the age of 16.

Fourth Kenny chopper explosion

In July 2000, a chopper owned by Grant Kenny Ocean Air Helicopters and leased to the Capricorn Rescue Helicopter Service crashed near the Queensland town of Marlborough, killing the experienced pilot and four passengers.

In 1997, a helicopter leased by the company to the CRHS caught fire while on the ground and was destroyed.

In 1998, another Kenny-owned chopper leased by Channel 10 crashed into the side of Brisbane's Mount Coot-tha, killing the pilot.

Curry Kenny Aviation Group spokesman Andrew Crook said the pilot in yesterday's smash was experienced, and had flown over Purnululu (also known as the Bungle Bungles) for several years.

"We are obviously deeply saddened and shocked about what's happened," Mr Crook said.

"We are working with all the regulatory authorities to find out what did happen and whatever we can do to assist in that we will."

Mr Crook would not comment specifically on the company's safety record, referring questions to the Australian Transport Safety Bureau.

"The Curry Kenny Aviation Group certainly takes all its responsibilities in this regard to the highest degree," he said.

Mr Crook pointed out that the company was the largest private owner of aircraft in Australia.

While there had been another safety incident at the company in the past year - in which a pilot was at fault - Mr Crook denied the Curry Kenny Aviation Group had a bad safety record.

"Maintenance is conducted at the highest levels ... there's nothing to suggest there's anything wrong with the Curry Kenny Group," Mr Crook said.

Australian Transport Safety Bureau director of aviation safety investigation Julian Walsh would not comment on the cause of the crash.

He said the safety record of Kenny's company would be examined as a matter of course.

"The helicopter that went down was a Robinson R44," Mr Walsh said.

"They're a very popular US-built aircraft.

"There's nothing in particular of concern in relation to those helicopters."

Police Operations Centre spokesman George Putland said the chopper was headed for Echidna Chasm but crashed on level ground two kilometres short of the local landmark.

The helicopter was one of three Slingair Heliwork craft flying in the area.

The alarm was raised by one of the helicopters when the pilot saw smoke on the horizon and could not contact the crashed chopper by radio.

The Department of Environment and Conservation fought the bushfire and shut Bellburn Airstrip down overnight.

The airstrip abuts a bush camp in world heritage listed Purnululu, about 55km by air from the township of Warmun formerly known as Turkey Creek.

Inspector Putland confirmed the fire was not a threat to campers or campsites in the area.