Twenty people were injured, 12 seriously, after an incident with a tourist boat at the Kimberley attraction in Horizontal Falls threw customers overboard.
Police and emergency services are in northeast Broome, Western Australia, where the ship is believed to have capsized or landed.
WA Regional Police Commander Brad Sorrell said there were 26 tourists and two crew members on board when the incident occurred around 7 a.m. in the remote area, only accessible by air and sea.
Emergency calls were made around 7:15 a.m. and first aid arrived at 8:30 p.m.
“Some people were found in the water and were rescued,” he said.
None of the injured were children and none of the injuries appeared to be life-threatening.
Four Royal Flying Doctor Service planes have been deployed with six doctors and six flight nurses, with two planes and crews already at the scene, evaluating and treating patients on the boat.
Local helicopter services are helping to get some patients on the plane and there is a makeshift sorting station.
Three other RFDS doctors are providing coordination and telephone assistance from an operations center in Jandakot, a suburb south-east of Perth.