More than 1,000 US marines begin arriving in the Top End and say they are ready for whatever may happen as North Korea escalates its nuclear threat.

The first group of 1,250 marines touched down in Darwin on Tuesday morning for their sixth annual dry season rotation in the Top End.

Their arrival comes as Foreign Minister Julie Bishop defended US President Donald Trump's "they gotta behave" message to North Korean leadership after its failed missile test on Sunday.

"[North Korea] is on a path to achieving nuclear weapons capability and we believe Kim Jong-un has a clear ambition to develop an intercontinental ballistic missile capable of carrying a nuclear payload as far as the US," Ms Bishop said.

"That would mean Australia would be in reach so unless it is prevented from doing so, it will be a serious threat to the peace and stability of our region, and that is unacceptable."

In Darwin, the rotation's commanding officer Lieutenant Colonel Brian Middleton said the force was ready, come what may.

"Any time a marine force is forward deployed, we are always on standby for anything," he said.
He said this year's contingent was "the most robust package" the marines had put together for training in the Top End, featuring an "ace aviation combat element" of 13 aircraft.

Over the next two weeks, the deployment's largest fleet of military aircraft yet will be brought to Australia as part of the agreement, including four high-speed troop transporters, the MV-22 Osprey, five Super Cobra helicopters and four Huey helicopters. The next six months will see the troops train with their Australian counterparts and other nations, including Japan and China.

GIANT birds of prey will hover the Territory’s skies as part of this year’s US Marines deployment in the Top End.

A number of Osprey tilt-rotor aircraft are heading to Darwin to quickly deploy the 1250 marines who will soon be calling the city home for the next six months.

The Osprey aircraft take off and land like helicopters but can fly like planes.

While the US Marine deployment will have the same number of personnel as the previous, the new rotation will have superior aircraft numbers supporting it.

As well as the Ospreys there will be five AH-1W Super Cobras and four UH-1Y Venoms.

The officer in charge of the forward co-ordination for Marine Rotational Force – Darwin, Lt. Colonel Matthew Emborsky, said the Osprey’s speed and distances it could operate in made it perfect for the Territory outback.

Last year the marines were supported by just four Huey helicopters.

The Ospreys will be based at Royal Australian Air Force Base Darwin and will become a regular feature in our skies.

“Bradshaw Field Training Area, where our marines drill, is an eight-hour drive from Darwin … the Osprey can get there in an hour,” Lt. Colonel Emborsky said.

THE US military presence in the Territory is likely to be enhanced under President Donald Trump, Prime Minister Malcolm Turnbull confirmed yesterday.

Around 1250 US marines and 13 aircraft will be deployed to the Top End in April.

It will be the third and most complex rotation of US troops.

“We have a strong ally in Washington and the US’s continuing strong presence in our region, which President Trump has committed to, is of vital importance for all of us,” he said.

“I expect, based on discussions I’ve had with the US President, the US presence in the region will remain strong and is more likely to be enhanced. We’ve seen General (James) Mattis, the new Defence Secretary, has been travelling through the region providing very strong reassurance to America’s friends and allies in the region."

The US Marines are coming to Darwin. That’s the firm opinion of Australia’s Defence Force.

An ADF spokesman said the marine presence in Darwin would not change under the new administration of US President Donald Trump.

He said Australia and the US were now working on full implementation of a 25 year defence agreement between the two countries.

This year’s US Marine rotation, arriving in Darwin in April, is forecast to be the most complex Marine Air Ground Task Force deployed to Australia.

Around 1250 marines and up to 13 aircraft, including four MV-22 Ospreys, will create opportunities for more complex and sophisticated training activities.

Concerns about the deployment had been raised following Mr Trump’s election as US President and his comments that allies should contribute more financially towards a US military presence in their countries.

“No, there is no suggestion that the marine deployment to Darwin is up for review,” an ADF spokesman said.

“The size and composition of each marine rotation to Australia is mutually determined based on the nature of the training, planned regional engagement activities, other resource commitments and respective national priorities,” the ADF spokesman said. “As this is a 25 year agreement, it was important to reach a sustainable approach for both sides ... we continue to work closely with the US to refine infrastructure requirements and implementation plans to support MRF-D rotations into the future.”

A United States Defence build-up in the Northern Territory is being welcomed by local businesses and watched closely by wary northern neighbours, as some of the world's deadliest fighter aircraft arrive.

Defence analysts say the increasing presence of US Marines in the Top End is a clear sign the US is bolstering its military presence in the region, as a squadron of its sophisticated F-22 Raptors touched down near Katherine this weekend for three weeks of exercises with the Australian military.

That will soon be followed by the next rotation of US Marines and a large contingent of aircraft.

The Defence Department said it constituted the largest and longest rotation of fifth-generation aircraft to Australia to date.

Dr John Blaxland from the Australian National University's Strategic and Defence Studies Centre said it was clear "the US has a much more robust presence in Australia."

Dr Blaxland said while there was "a fair degree of assurance" the current arrangement with US troops in Darwin would remain, "in terms of the US posture in South East Asia and the region more broadly there's enormous uncertainty".

"Does this mean the US administration will take a more confrontational approach towards China, say, in the South China Sea?

"If that's the case that has potential to have significant consequences in the neighbourhood; there'll be considerable pressure on Australia to participate and to facilitate that engagement."

Chief Minister Michael Gunner said he would work hard to help local businesses seize the opportunity of Defence contracts over the coming years. "I'll be in Canberra, knocking on doors, I will be opening them, and sometimes as the Chief Minister I can open doors the private sector can't," Mr Gunner said.