Two helicopters collided mid-air killing four people Monday on Australia's Gold Coast, officials said, with images showing one of the aircraft's rotors lying on a sand bank.
Three other people are in a critical condition, police said.
One helicopter lay flipped over on the sand a few metres from the shore. Its rotors lay a short distance away.
The other chopper appeared to be largely intact at the accident scene, which is near the popular Sea World marine theme park.
A rescue helicopter landed on the sand nearby, its rotors spinning, images of the aftermath showed, as scores of rescuers spread around the area.
Several police and rescue vessels stood by near the sandbank.
"As a result of [the crash], four people have lost their lives today," said Queensland police service acting inspector Gary Worrell.
Australia's transport safety bureau launched an investigation into the incident, which it described as a "mid-air collision".
Investigators were expected to arrive shortly to examine the wreckage and map the site, as well as recover components for examination, it said in a statement.