Two people dead after helicopter crashes off Whitsunday Islands

Two people are dead and three others injured after a helicopter crashed into waters off Queensland's Whitsunday Islands.

The Civil Aviation Safety Authority says five people were aboard the Eurocopter 120 which went down near Hardy Reef Pontoon on Wednesday afternoon.

Queensland Police confirmed two people had died in the crash at about 3.35pm on Wednesday, while three people were being treated for non-life-threatening injuries.

"A man and a woman who are believed to be international tourists were recovered from the helicopter and pronounced deceased at the scene," a Queensland police statement said on Wednesday night.

Three other people, including the male pilot and a male and female passenger, also believed to be from overseas, would be taken by sea to a medical facility for treatment.

It is understood the helicopter crashed into water 250 metres from the pontoon.

The Australian Transport Safety Bureau (ATSB) issued a release on Wednesday evening confirming a crash investigation was being launched.

"A team of Transport Safety Investigators will soon travel to the accident location to commence the evidence collection phase of the investigation," an ATSB statement said.

"There, investigators will interview witnesses, examine any available recorded data, review operational records and technical documentation amongst other activities."

Police will assist the ATSB with the investigation and recovery of the aircraft.

It's unclear at this stage if the flight was a private charter to the popular tourist destination but at least one helicopter tour operator in the region operates the type of aircraft involved in the accident.

The pontoon, 65km northeast of the Whitsundays, allows underwater viewing chambers with tourist operators in the area saying Hardy Reef offers an excellent combination of reef, coral and fish life for tourists.

The well-known Heart Reef is also nearby.