The Queensland Ambulance Service has confirmed nine people in total have been taken to hospital for further treatment.

One of those patients was taken to the Queensland Children's Hospital, but QAS hasn't confirmed the ages of those involved.

ABC News reporter Lillian Rangiah is not far from the scene of the crash.

She says windy weather and the location of the incident hindered the emergency service response, and the area in general is quite busy at the moment due to the holiday period.

"There's been holiday-goers who have told the ABC they can't believe what has happened, in fact some witnessed the crash," she says.

"People just can't believe this slice of paradise has seen such a great tragedy here today."

Acting inspector Gary Worrell from the Queensland Police Service says multiple members of the public rushed to help after seeing the two helicopters crash near the Sea World theme park.

He says one of the helicopters landed upside down on a sand bank, and both bystanders and police tried to pull those in the cabin to safety.

"Those people were confronted with a significant incident," he said.

Police have confirmed the deaths of four people in a collision between two helicopters.

Three people are in a critical condition in hospital.

It's understood the four people who died and the three people critically injured were all in the same helicopter.

Initial inquiries suggest one helicopter was landing and one was taking off when the collision occurred.

Jayney Shearman from the Queensland Ambulance Service says all available resources were deployed when reports came through that two helicopters had collided.

She says the condition of those who survived the crash ranges from minor to critical, and that everyone has been taken to hospital.

She described the incident as "very traumatic".

There's a major emergency service response around the Sea World/Main Beach area.

This update was shared by QAS a little earlier:

It's still unclear how many people have died in the crash, and the conditions of those who survived are still unconfirmed as well.

We're due to hear from police soon.

Officers at the scene will be speaking to media in the next 20 to 30 minutes.

We'll bring their updates to you here as they come through.

The Australian Transport Safety Bureau has released a statement saying they're investigating a "fatal mid-air collision involving two helicopters near Seaworld on the Gold Coast".

The ATSB hasn't confirmed any details about how many people have died or the conditions of any other people involved.

The statement, from ATSB Chief Commissioner Angus Mitchell, says investigators are travelling to the scene from Brisbane and Canberra, and are expected to arrive this afternoon.

"The ATSB asks anyone who may have seen the collision, or who witnessed the helicopters in any phase of their flights, or who may have footage of any kind, to make contact via witness@atsb.gov.au at their earliest opportunity," the statement reads.