A US military Boeing MV-22B Osprey tilt-rotor aircraft carrying 23 marines crashed on Melville Island, 80km north of Darwin on Sunday morning.
Three Americans have been confirmed dead and five were transferred to Royal Darwin Hospital on Sunday night, one in critical condition.
Six have serious injuries and 13 are "walking wounded" with broken bones but were able to assist paramedics with transfers.
Investigations are underway as to what caused the crash, though the operation on the island has turned from a rescue mission to a recovery mission, NT Commissioner Michael Murphy said on Monday morning.
"(The deceased) are part of the recovery operation at the moment," Mr Murphy told ABC radio.
A Code Brown alert declared at Darwin hospital on Sunday, the country's highest level of alert, was lifted on Monday morning.
The Department of Defence said the incident occurred during Exercise Predator's Run 2023 and no Australian Defence Force members were involved.
Defence Minister Richard Marles told ABC radio local services were on the scene of the crash "almost immediately".
"I think that's played a really important part in making sure we've had as many people survive as possible from this crash," he said on Monday.
"Twenty-three people were on board and 20 people have survived the crash, which is remarkable."
He said questions over the safety of the Osprey aircraft were a matter for the US Defence Force but Australia would rely on US certification and safety processes when operating with US forces when Ospreys were deployed.
The Marine Osprey aircraft has a tumultuous history, with a number of mechanical and operational issues since its introduction in the 1980s.
Since 2012, 19 people have died in six crashes involving the Osprey.
Opposition Leader Peter Dutton said the government was doing everything it could.
"(The families) will be feeling this loss very acutely. So we pass out our thoughts and our prayers on to all of those who are affected by this tragedy," he said on Monday morning.
ANU security expert John Blaxland told SkyNews the crash would have long-term emotional and physical repercussions.
Those who are obviously maybe less seriously injured, but still pretty severely traumatised by the experience, they can slip incredibly quickly," he said.
"The very violent movement that can have long-term repercussions as well."
US Defence Secretary Lloyd Austin also issued a statement on the dead and injured marines.
"These marines served our country with courage and pride and my thoughts and prayers are with their families today and with the other troops who were injured in the crash and with the entire US military community family," he said.
The US embassy on Monday issued a statement thanking members of the rescue operation.
"Australians and Americans have been the closest of friends for over 100 years and we're thankful for their continued friendship and support at this time," it said.
About 150 US Marines are stationed in Darwin and taking part in military drills alongside personnel from Australia, the Philippines, East Timor and Indonesia.
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