YOKOTA AIR BASE, Japan — More than 1,000 Marines will train in Australia over the next two weeks, testing the waters for the six-month deployment of a battalion-size force there next year.

The Marines, who have been building their presence in Australia’s Northern Territory since last year, sent 200 to 250 personnel Down Under this summer as part of Marine Rotational Force–Darwin (MRF-Darwin).

The force is set to increase next year to 1,150 personnel, including a Marine battalion and helicopters. Plans call for 2,500-strong Marine Air Ground Task Forces to travel to Darwin on six-month rotations each year starting in 2016.

Exercise Koolendong 2013, which started Tuesday and will run for two weeks, includes MRF-Darwin personnel already in Australia and 750 Marines and sailors from the 31st Marine Expeditionary Unit (MEU). They will train alongside the 5th Royal Australian Regiment at the Northern Territory’s 3,300-square-mile Bradshaw Field Training Area, according to a Marines statement.

“Exercise Koolendong 2013 is designed as a ‘proof of concept’ to assess the capacity of the Bradshaw Field Training Area to accommodate live-fire training for battalion-sized units of approximately 1,000 personnel and demonstrate the capabilities that U.S. amphibious forces can provide,” the statement said.

The 31st MEU Marines, transported to Australia by the Bonhomme Richard Amphibious Ready Group, are the force of choice for the Asia-Pacific region, 31st Marine Expeditionary Unit commander Col. John Merna said in the statement.

“We can move personnel and equipment… and bring what we need to sustain ourselves… for this exercise without significant external assistance,” he said.

31st MEU operations officer Lt. Col. John Lehane said the exercise would show the Australians the balance, flexibility and operational reach of U.S. amphibious forces.

Koolendong will include training with machine guns, mortars and artillery as well as bombing runs by AV-8B Harrier jets from the 31st MEU and FA/18D Hornets from Marine All- Weather Fighter Attack Squadron 242.

MV-22 Ospreys, CH-53E Super Stallions and Huey helicopters from the 31st MEU will provide transportation for Marines from the USS Bonhomme Richard, the Marines statement said.

MRF-Darwin personnel will depart Australia next month, according to Marines spokeswoman 1st Lt. Savannah Moyer.

robson.seth@stripes.com