Four people have died after a mid-air collision between two helicopters near Seaworld on Australia's Gold Coast.

Queensland Police say initial investigations suggest the crash happened as one aircraft was taking off and the other was landing.

Those who died were travelling in the same helicopter. Three other passengers are in a critical condition.

Five of the six people on the other aircraft, which made an emergency landing, suffered minor injuries.

The Australian Transport Safety Bureau (ATSB) is investigating the collision, which happened at about 14:00 local time (04:00 GMT).

The two aircraft came down near a tourist strip known as Main Beach, about 75km (47 miles) south of Brisbane.

Gary Worrell of the Queensland Police Service told reporters the four deaths and three serious injuries had all occurred in the same aircraft.

"It's a difficult scene," he said. "Due to the area it's located, on the sand bank, it was difficult to gain access, to get our emergency services to the scene to manage it appropriately."

Images from the crash site show debris strewn around the area and a mangled helicopter apparently lying upside down opposite the Seaworld resort.

The other helicopter has the popular marine park's logo on its fuselage and appears to have made an emergency landing after the collision.

According to the Seaworld website the park offers sightseeing helicopter flights for tourists, as well as carrying out other charter operations.

Seaworld Drive, the main access road to the marine park, has been closed to traffic by local police.

They urged motorists and pedestrians to avoid the area as first responders inspect the scene.

Investigators from the ATSB's offices in Brisbane and Canberra are being deployed to the scene to gather evidence, examine the wreckage and interview witnesses.

ATSB chief commissioner Angus Mitchell has also asked eyewitnesses who saw the collision or the helicopters in flight to contact investigators.

A preliminary report will be made public in the next six to eight weeks, with a final report to follow once the investigation is complete, he added.

The Gold Coast region is currently in its peak tourist season, with children on their summer breaks.