Canberra has been accused of dragging its heels over the deployment of 2500 US marines to Darwin­ just as a major report commissione­d by the Pentagon recommended steps to allow northern Australia to act as a “sanctuary” for US forces in the event of conflict in Asia.

The report, revealed by The Weekend Australian on Saturday, found Australia was becoming “more central” to US military strategy in Asia, and Washington would “increasin­gly rely on Aust­ralia for some critical capabilities”.

Up to 2500 marines were expected to be stationed on six-month rotation in Darwin from this year, under an agreement first announced by US President Barack­ Obama and then prime minister Julia Gillard in 2011.

Troop numbers have been steadily increasing with each dry-season visit, but reached only about 1150 last year. The deadline for full deployment has been pushed back till 2020. Northern Territory Chief Minister Adam Giles yesterday blamed Canberra for the delay.

“I think our partnership with the US is a fantastic partnership and I would like to see it roll out larger and I would like to see it roll out quicker,” Mr Giles said.

The Minister for Defence, Marise Payne, said it was in “Australia’s national interest for the US to be engaged in our region” as that country’s economic, political and military focus shifted towards Asia.

“Australia continues to work closely with the US to progress toward­s rotations of about 2500 US marines and equipment by 2020,’’ Senator Payne said.

“The 2015 rotation involved around 1150 US marines, four helicopters and a range of vehicles and equipment.

“The 2016 rotation is expected to build on that, with an increase to the number of marines and equipment. Australia’s priority is to ensure­ the initiatives are fully implemented in a considered manner­.”

Negotiations are understood to be quietly taking place about what infrastructure and other facilities US forces would need to increase their presence in the Top End. Ms Payne said work was under way to finalise cost-sharing arrange­ments, and it was important the arrangements, expected to at least 25 years, were done right.

Labor Opposition Leader Mich­ael Gunner said that most Territ­orians were “comfortable” with the existing US troop presence, but significant consultation would be required if the temporary rotations were ever to become full-time deployment.

He attacked Mr Giles’s “shortsighted … cash grab” of leasing Darwin Port to a Chinese firm.

About 50 US marines are understood to be permanently stationed­ in the Top End, with equipment stored at various locations­. The US also has a permanen­t presence at Pine Gap, near Alice Springs.