They arrived into port to the trumpets of the Tongan military brass band.

The HMAS Adelaide and HMAS Melbourne docking at the port of Nuku’alofa was a sign of strength and stability, and it needed to be, as China extends its economic reach into the Pacific.

In Tonga, external debt to China represented nearly a third of its gross domestic product in 2011.

The country now facing a certain level of debt distress, one of the risks of reaching into Beijing’s deep pockets.

Australian personnel are in the South Pacific for the Indo-Pacific Endeavour. Picture: 9NEWS (9NEWS)

The ships show Australia's resolve to maintain its presence in the region. Picture: 9NEWS (9NEWS)

Now Australia’s biggest warship is leading the charge on one of the most significant military missions through the South Pacific, as part of the Indo-Pacific Endeavour.

Defence Minister Marise Payne said the IPE 18 is one of the Australian Defence Force’s most important annual activities and represents a major contribution to regional security and stability.

As a demonstration to the island nation of Tonga of that partnership, Ms Payne today handed over five Australian-gifted Unimog vehicles, reflecting our commitment to the local armed forces.

The official handing over took place onboard the HMAS Adelaide, Australia’s most sophisticated helicopter landing ship.

The Canberra-class assault ship weighs 27,800 tonnes and measures 230 metres in length.

The handing over of the vehicles took place on the HMAS Adelaide. Picture: 9NEWS (9NEWS)

The ship includes a 50-bed hospital. Picture: 9NEWS (9NEWS)

It is a floating city, hospital and airport, of sorts.

The ship is designed to provide medical and humanitarian assistance during regional emergencies, with a 50-bed hospital, and the ability to produce 156,000 litres of fresh water a day.

It also has five gyms, a basketball court and a galley kitchen which churns out 6000 meals a day.