Two helicopters collided in an Australian tourist hotspot on January 2 afternoon, killing four passengers and critically injuring three others in a crash that drew emergency aid from beachgoers enjoying the water during the southern summer.

According to acting Queensland state police inspector Gary Worrell, the two helicopters that collided at the Sea World amusement park in Main Resort, a northern Gold Coast beach, appeared to have been taking off and landing, respectively.

One helicopter appeared to have been taking off and the other landing when they collided near the Sea World theme park in Main Beach, a northern beach on the Gold Coast, Gary Worrell, Queensland state police acting inspector, said at a news conference.

One helicopter landed safely on a sandbank, but debris from the other was spread across an area police described as difficult to access.

Australia's transport safety bureau launched an investigation into the incident, which it described as a "mid-air collision".

Passengers in the other helicopter, which lost its windscreen in the crash, are also receiving medical assistance. Footage of the crash showed a helicopter shortly after takeoff being clipped by another helicopter flying over the water.

Queensland Premier Annastacia Palaszczuk said the accident was an unthinkable tragedy. "My deepest sympathies are with each of the families and everyone affected by this terrible accident," she said.

Queensland Ambulance Service said earlier that 13 people were being assessed for injuries.The Gold Coast region is at its busiest in January, the peak time for holidays in Australia's summer.