An American Marine has been arrested and charged after allegedly raping a woman in Palmerston, near Darwin in the Northern Territory.

A US Defence Force spokesman confirmed a 20-year-old Marine was arrested by NT Police and charged with aggravated assault and sexual intercourse without consent.

A NT Police spokeswoman said the 20-year-old’s arrest on Monday, September 18, was in relation to an alleged incident in Palmerston that same day.

It is understood that all Marines at the Robertson Barracks are unable to leave or allow visitors on base, with the US Defence Force spokesman saying there was a “restricted liberty status” at the base.

The American military has taken over an investigation into the death of three Marines during a training exercise on a remote island off the Northern Territory.

NT Police were leading the response after a horror military aircraft crash on the Tiwi Islands on Sunday August 27.

There were 23 troops on board the tilt-rotor military aircraft when it went down, with the two pilots and crew chief understood to have sacrificed their lives to avert a catastrophic crash killing all on-board.

Under the Commonwealth Defence Visiting Forces Act, the Territory coroner was barred from holding an inquest into the three marines’ deaths with the initial reports passed onto the American authorities.

A new US Air Force will build a "mission planning" and operations centre in Darwin, as part of $630 million in American spending across the top end over the next two to three years.

The "Squadron Operations Facility" in Darwin will add to its growing array of military assets in the north, raising fears Australia may be locked into any future military conflict between China and the USA.

The tender documents say the Squadron Operations facility in Darwin will be used for maintenance, mission planning, intelligence and crew briefings — it is budgeted to cost $US26 million ($40 million).

“Being able to organise and deploy forces outside of the dense missile attacks that China is likely to use against places like Guam and Okinawa is part of the strategic logic,”

British soldiers based in Australia could be part of the next step to bringing the two military forces closer together.

UK Armed Forces Minister James Heappey said stationing British troops in Darwin, where US marines have a presence, was "not impossible" as his nation looked to expand its influence in the Pacific.

"It comes up quite regularly in conversation about what the Aussies and the US are doing up there and whether we should be there too," he said.

The minister said the UK was still in a discovery phase in the Pacific and military deployments to Australia were a better option than basing British troops on more contested territories in the region. He said the UK was working careful to expand its presence in the Pacific with concerns moving too fast or being too heavy handed might do more harm than good by alienating partner nations.

The Northern Territory facility that gained national prominence as the "gold standard" for quarantine during the COVID-19 pandemic will be used to house thousands of troops form both Australia and overseas under a new lease agreement struck by the federal and NT governments.

The 3,500 bed former COVID-19 quarantine facility will be used to house thousands of military personnel from Australia and overseas under a new five-year deal between the federal and NT governments.

The first large cohort to be housed at the facility — 1,300 troops from Australia and international partner nations taking part in Exercise Talisman Sabre — is due to arrive later this month.

"The importance of this facility is it will take pressure of the local accommodation market during a crucial time for the NT tourism season, and that will ensure that there's more beds for tourists to come to."