The United States has stunned many in the Pacific, announcing it will partner with Australia in developing a joint naval base in Papua New Guinea.
The revelation was delivered during a stinging speech by American Vice President, MIke Pence at the APEC Summit, warning pacific nations not to accept over-burdensome loans from China -- loans often sneeringly referred to as 'debt diplomacy.'

"Today it's my privilege to announce that the United States will partner with PNG and Australian on their joint initiative on their base on Manus Island," he said.

Prime Minister Scott Morrison earlier foreshadowed the announcement in an earlier speech, "Australia is stepping up. We will step up. [We are] stepping up to a whole new level."

China would see this as an affront to their strategic ambitions in the Pacific region.

The presence of more than 1500 US marines in Darwin should be welcomed and is a "really positive engagement", Defence Minister Marise Payne says.

Senator Payne made the comments after viewing a computer simulation exercise involving Australian and US forces in which bombs explode in Darwin's Cullen Bay and the troops respond during a visit to Robertson Barracks in the Top End.

The simulator can be used for mission rehearsal exercises for any scenario before going to an "operational or live firing environment", Australian Army's Major Max Williams told the minister.

The number of US marines in Darwin has been gradually increasing to 2500 since first being stationed in 2012.

There are 15 different joint training exercises planned over the next six months.

The meeting comes at a time of increased tension between China and both the US and Australia. The US withdrew an invitation to China to attend the Rim of the Pacific naval exercises this year and US Secretary of Defence James Mattis warned Beijing during a speech in Singapore last weekend of consequences over its aggression in the South China Sea.

THE Australia-US alliance has never been more important, Defence Minister Senator Marise Payne said during her Top End visit on Tuesday.

Senator Payne, who was in Darwin with top US and Australian military brass, said the presence of the US Marine task force in Darwin represented a significant opportunity.

Questioned on China’s island expansion in the South China Sea, Senator Payne said Australia has been very clear about its position.

“We have encouraged all claimants – and it is important to remember there are multiple claimants – to resolve those issues peacefully in accordance with international law and according to the rules based global order,” Senator Payne said.

“We demonstrate that by our engagements in terms of freedom of navigation and freedom of over flight.

“The United States demonstrates its position according to its own approach.

DARWIN, Australia —The past casts a long shadow over this palm-lined city on Asia’s fringe. Allies upgrade facilities and Marines expand operations as China extends its reach. Darwin’s location, 400 miles from the Indonesian archipelago and 1,700 miles from the South China Sea, provides what could serve as a springboard for U.S. forces in the region.

For the U.S., Australia’s benefits go beyond confronting China. The alliance allows the U.S. to disperse forces and offset a lack of permanent bases in the Pacific outside Japan and South Korea, particularly for aircraft.

US marines will soon embed on Australia's largest warship for a tour of Pacific island nations, as anxiety continues to grow among western allies over China's rising influence in the region.

Preparations are almost complete for the Australian Defence Force's Joint Task Group mission, centred on the amphibious Landing Helicopter Dock, HMAS Adelaide.

Defence sources have confirmed several dozen US marines, who are part of a current rotation in Darwin, would also be embedded on HMAS Adelaide ahead of the RIMPAC war games in Hawaii in July.

"There is a connection that could be made between the geopolitical competition that we're starting to see unfold in the Pacific, with China becoming more present as an actor (including military deployments that will become more regular in the future) and Australia doesn't want that gap to be filled by outside actors." ^/s