More than 20 passengers have been injured, 12 of them seriously, on a tourist boat that ran into trouble off Western Australia's Kimberley Coast.
The Royal Flying Doctor Service led the emergency response to the incident at Horizontal Falls, about 250km northeast of Broome, on Friday.
Four aircraft with six doctors and six flight nurses were deployed to the scene, assessing and treating patients on the boat.
The first group of patients with minor injuries were taken by seaplane to Broome Hospital for further assessment.
About 12 patients with serious injuries were to be transferred to either Perth or Broome for treatment.
Authorities said local helicopter services were providing assistance to winch some patients to safety.
Perth police said it was their understanding that the incident involved the capsize of a tourist vessel but that was still to be confirmed.
Tour operator Horizontal Falls Seaplane Adventures said in a statement it was working with authorities to help injured passengers and manage the incident.
"Falls Express, guided by an experienced skipper during an early-morning tour, was involved in the incident while travelling through the falls," the statement reported by the ABC said.
"The vessel immediately returned to the pontoon."
The company said 26 passengers and two crew were on board at the time.
Broome police said the incident was ongoing but none of the injuries were believed to be life-threatening.
The area is host to regular jet boat tours through the quick-moving Kimberley tides.
The falls are a natural phenomenon where 10m of water surges through two narrow chasms at Talbot Bay.
