The ABC is reporting senior defence and federal government officials conceded the proposal may anger China even though it would be built as an industrial port.

However if approved it could eventually accommodate “large amphibious warships” such as landing helicopter docks and US military ships.

The ABC said it approached the Defence Department and the US Embassy in Canberra for comment, but both are yet to respond to detailed questions on timing and costs.

In a statement, the department said “Defence has no plans for the development of a new naval facility in the Northern Territory” while the US embassy declined to comment.

The NT Government says it is unaware of any plans for a US war base in Darwin.

In his first official visit to Darwin in May, US Ambassador to Australia Arthur Culvahouse said US relations to Australia were expected to build in the coming years.

Gunn Point Rd recently underwent $38 million upgrades which saw the resealing of the 35km stretch of road as well as resealing of Murrumujuk Rd.

Days prior to the revelation that a new port which could be used by the US Marines was being planned on the edge of Darwin, a placard popped up on one of the city's main commuter arteries.

"No USA war base" blared the letters of the sign hanging off the Bagot Road pedestrian bridge, which neighbours land owned by Australia's Defence Department.

Other similarly slapdash carboard banners were also erected along the street.

Their appearance signalled that some within the tropical capital may have been aware of the impending news — and perhaps the rest of the region's residents shouldn't have been too surprised.

While nothing has yet been declared through official government or Defence channels, the signs of such a development have long existed.

Whether or not the NT will see more foreign boots on the ground, the ADF has been steadily improving and upgrading defence infrastructure in and around Darwin in recent years — a fact which falls somewhat contradictory to the reality that ADF numbers have been on a steady decline in Darwin for the past decade.

Secret planning has begun for a new port facility just outside Darwin which could eventually help US Marines operate more readily in the Indo-Pacific.

Precise details remain tightly guarded but senior defence and federal government figures concede the proposal may risk angering China even though it's a commercial port, not a new military base.

Multiple officials, speaking on the condition of anonymity, have confirmed to the ABC the multi-use development would be in the Glyde Point area, roughly 40 kilometres north-east of Darwin's existing port.

Darwin port, which was controversially leased to a Chinese company in 2015, has existing defence facilities such as a multi-user barge ramp, but the new proposed facility would have the additional advantages of being less busy and less visible.

If approved, the new port could eventually be able to accommodate large amphibious warships such as Australia's Landing Helicopter Docks, and American vessels such as the USS Wasp, which recently arrived in Sydney.

Strategic experts believe a new deep-water port would be ideally suited for the more than 2,000 US Marines and their equipment during regular rotations through the Top End.

"The Americans are clearly not withdrawing from the Indo-Pacific, whether it's because of their strategic competition with China or more generally," said Rory Medcalf from the Australian National University.

It's understood a formal announcement on the new maritime facility could be made as early as next month when the "Talisman Sabre" war games with the US begin in the Northern Territory and Queensland.

A US Marine has died in a training accident at the Mt Bundey Training area after suffering injuries in a tactical vehicle accident on Saturday.

Lance Corporal Hans Sandoval-Pereyra died yesterday after succumbing to injuries suffered in the incident which saw one other marine suffer minor injuries.

He was conducting routine training at the training facility when the incident occurred and was initially treated at the scene before being medically evacuated by helicopter to Royal Darwin Hospital.

Commanding Officer for Marine Rotational Force — Darwin Colonel Russ Boyce said efforts were unsuccessful in saving the Marine’s life who was a valued member of the Marine Corps.

“We are saddened by the loss of Lance Corporal. Sandoval-Pereyra. He was a beloved member of our community and our deepest sympathies go out to his family and friends,” he said.

“We are extremely grateful to our Australian partners for their valiant efforts to save this young Marine’s life.”

The second Marine has been released from Hospital.

A recent survey suggests U.S. Marines are being welcomed with open arms by residents of Australia’s Northern Territory.

There’s been a steady build-up of Marines in Darwin, Australia, since 2012.

On May 1, with the Marines’ rotational force poised to reach its target of 2,500 troops, the Australian government released a report showing that Darwin leaders and residents have a generally positive view of the U.S. military presence.

Auditing firm KPMG’s “US Force Posture Initiatives (USFPI) Social and Economic Impact Study” involved a telephone survey of 408 locals and meetings with 27 key representatives from business, government and the community.

It shows 51% of people there have positive feelings about the U.S. troops with only 6% responding negatively.

That’s a contrast with Okinawa, Japan, for example, where criminal behavior periodically works against the U.S. cause, as was the case on April 13, when a U.S. sailor apparently fatally stabbed a Japanese woman and then killed himself, according to Japan’s Foreign Ministry.