SYDNEY - Australia will spend A$1.5 billion ($966 million) to boost maritime surveillance of its northern approaches, buying more long range drone aircraft and upgrading Poseidon maritime patrol aircraft.

The fleet of 14 Boeing P-8A Poseidon Maritime Patrol aircraft will have anti-submarine warfare, maritime strike and intelligence collection capabilities upgraded, Minister for Defence Industry Pat Conroy said in a statement on Tuesday.

A fourth Northrop Grumman manufactured MQ-4C Triton drone aircraft, developed with the United States Navy, will be based in Australia's Northern Territory, closest to Asia, and operated by a newly formed squadron in South Australia state.

The Triton will provide long-range surveillance of Australia's maritime region, the statement said.

"The purchase of an additional Triton will enhance operations from Australia's northern bases, a priority under the Defence Strategic Review," said Conroy.

The review in April said United States was no longer the "unipolar leader of the Indo Pacific", that intense competition between the U.S. and China was defining the region, and that the major power competition had "potential for conflict".

It recommended the country's northern bases become a focal point for deterring adversaries, and protecting trade routes and communications.

Australian Poseidon aircraft have conducted patrols in the East Vietnam Sea, and have also operated out of a Japanese airbase to enforce United Nations Security Council sanctions on North Korea.

Conroy said the Poseidon aircraft upgrades will strengthen the protection of Australian "maritime interests".

($1 = 1.5523 Australian dollars)