Two helicopters have collided near a marine theme park in the Australian state of Queensland, killing four people and leaving three others critically injured.

The mid-air collision, just outside Sea World on the Gold Coast, happened at around 2pm local time when the park would have been busy with families enjoying the summer school holidays.

Initial information suggested one of the helicopters had been taking off and the other had been landing when they collided, Queensland Police Acting Inspector Gary Worrell said.

He thanked members of the public who were among the first on the scene, adding that the location – a sandbank – had made access difficult.

“One airframe had the windscreen removed and it has landed safely on the island, the other airframe had crashed and it was upside down,” Mr Worrell said.

“Members of the public and police tried to remove the people and they commenced first aid and tried to help these people to safety.”

Janey Shearman, from Queensland Ambulance Service, said 13 people had been on the two helicopters.

The three people critically injured were suffering from “multi-system trauma”, while six people with minor injuries – mainly from the impact of the glass – were also taken to hospital.

Australian Transport Safety Bureau Chief Commissioner Angus Mitchell said investigators would begin arriving at the scene shortly to look into what had happened.