“The two planes then collided, crashed and landed on a sandy beach just outside the SeaWorld resort.
“As a result, four people have died today and three others are in a critical condition in hospital.”
Ambulance supervisor Jayne Sherman said six other patients were treated for injuries mainly from glass shards.
“There were multiple injuries, what we call multi-system trauma, which means there was a lot of impact on the body,” he said.
The popular Gold Coast theme park was rocked by the tragedy.
“We and the entire flying community are devastated by what has happened and our deepest condolences go out to all involved and especially to the loved ones and families of those who died,” said a spokesman for SeaWorld Helicopters.
“We are co-operating with all authorities, including the Australian Transport Safety Bureau and Queensland Police.”
Premier Annastacia Palaszczuk expressed her condolences to all involved.
“What happened on the Gold Coast today is an unimaginable tragedy,” the Prime Minister tweeted.
“My deepest sympathies to each and every family affected by this terrible accident.”
Witness Jonathan James Spaknoll said the crash occurred when the rear rotor of one clipped the other after the helicopters came too close.
“Yes 2 helicopters collided with each other. One looks like it goes up and one looks like it comes back. Cutting across the back, the other landed on the sandbar. was behind us,” he wrote on Facebook.
Julie Connock said there was a huge explosion when the plane crashed.
“To see this happening live in front of us is tragic,” Ms Cannock said on social media.
“Very lucky for the families and boats on the beach where they crashed. .. So sad for the families that it was a beautiful days sightseeing tour.
Billy Dunks said on Facebook: “It saw something hit the car and it went straight down. I hope everyone is well.
People on jetskis and boats rushed to help victims on a small sand island from the theme park before paramedics and police arrived.
A life flight helicopter hovered over the scene before being seen on the flight tracker website moving to another site just before 3pm.
Chief Commissioner Angus Mitchell said the Australian Transport Safety Bureau was investigating the collision.
“The ATSB is asking anyone who witnessed the collision, or who saw the helicopters at any stage of their flights, or who has any footage, to contact [email protected],” he said.