Australia's ability to respond to humanitarian disasters has greatly increased after Prime Minister Tony Abbott announced on Friday the purchase of two additional Boeing strategic lift aircraft.

The acquisition of the latest pair of C-17A Globemaster III aircraft brings the number in the Royal Australian Air Force's ( RAAF's) possession to eight.

C-17s had been integral to recent Defense Force operations in the Pacific and across the world, Abbott said on Friday.

"Since they were first acquired at the initiative of the Howard government, C-17 aircraft have transformed the ADF's (Australian Defense Force's) capacity to transport large loads over long distances and to deploy its vehicles, helicopters and heavy equipment within Australia and overseas," Abbott said in a statement.

The aircraft were used to delivery equipment, aid pallets and personnel during relief efforts in the Operation Pacific Assist in the wake of the cyclone that devastated Vanuatu.

Relief assistance has also been provided to Japan after the 2011 tsunami, New Zealand after an earthquake ripped through Christchurch and closer to home in Queensland during numerous major floods.

Both aircraft would be ready to use by January 2017.

"Australia has worked closely with the United States Air Force to acquire the first aircraft within six months of the initial order and the second aircraft within 10 months of the delivery of the first. This will mean that the ADF will gain additional operating capability within a short time-frame."

Upgrades to the RAAF facilities at the Amberley base 50 kilometers southwest of Brisbane will cost almost 240 million US dollars bringing significant work opportunities to local industry.