"We are doing everything we can to return them safely to Darwin for treatment," Murphy told a press conference in the territory's capital Darwin, adding that Australian Defence Force and the US Marines were involved in the effort.

One marine was being operated on at Royal Darwin hospital and four others were at the hospital, said Northern Territory Chief Minister Natasha Fyles.

"We have more arriving as we speak... Some people are critically injured," Fyles told the news conference, adding there was a "wide range" of injuries.

Australian personnel were not involved in the crash that occurred during Exercise Predator's Run 2023, Albanese said.

"Our focus as a government and as a department of defence is very much on incident response and on making sure that every support and assistance is given at this difficult time," the prime minister told a previously scheduled press conference in Western Australia.