Turnball unveiled a "defense white paper" in Canberra on Thursday that included a doubling of Australia's submarine fleet to 24, nine new frigates and - for the first time - the purchase of seven US-made unmanned surveillance drones.

"Fragility" in western Asia, including territorial disputes involving six nations in the South China Sea, North Korean "instability," and Middle East conflicts all posed risks to Australia's and the region's security, Turnbull said.

He also cited "climate change, malicious cyber activists, pandemic disease and transnational terrorism" as potential threats.

Budget to double

By 2026, Australia's defense annual defense expenditure is to rise to A$58.7 billion (38 billion euros) or 2 percent of its gross domestic product (GDP) - consistent with average defense spending by many nations.

With Australia's current defense budget at about A$32 billion, its planned additional spending over the ten years will add up to A$195 billion.

Australia's announcement followed Tuesday's report by the Stockholm International Peace Research (SIPRI) that six of the world's ten largest arms importing nations are located in Asia and Oceania, another term used in the Pacific Ocean region.

Canberra's white paper proposes an expanded Australian defense force of 62,400 personnel, with the addition of 2,500 new roles, including 900 jobs focused on improved cyber, intelligence and aerospace security.

China should 'reassure' neighbors

Australian Defense Minister Marise Payne said China would be "important" for regional stability and urged Beijing to provide "reassurance to its neighbors by being more transparent about its defense policies."

The South China Sea is currently the scene of multifaceted territorial claims involving China, which uses dredged sands to extend islands, as well as Vietnam, Malaysia, Brunei, the Philippines, Taiwan.

In recent years, China and Japan have also argued over the Senkaku/Diaoyu Islands.

'Riding two horses'

Regional analyst Professor James Curran of the University of Sydney warned that Australia's bid to "ride two horses simultaneously" in both Washington and Beijing would require "very deft and delicate diplomacy" in the coming years.

Canberra will later this year decide on tenders for new generation submarines to replace its current diesel and electric-powered Collins Class vehicles.

Three consortiums in France, Germany and Japan are competing for the project.

To boost maritime surveillance, Australia also plans to purchase seven US-made MQ-4C Triton drones and eight P-8A Poseidon aircraft.

Turnball said within two decades "half the world's submarines and half the world's combat aircraft" would be located in the region from India to the Pacific.

Already included US-led operations

Australia is already part of the US-led campaign against "Islamic State" jihadists who hold swathes of western Iraq and northern Syria.

For years, the US has rotated Marines for training through Australia's northern hub of Darwin as part of President Barack Obama's "re-balancing" of US strategy in 2012 towards the Asia-Pacific region.

Long-standing US-Australian ties

Ties between the US, Australia as well as New Zealand go back decades to World War Two, when US forces led battles across the western Pacific to regain island territory seized by the-then imperial Japan.

Professor Payne said on Thursday that the United States would in the future "increasingly expect more from their allies in the region."

Obama 'chided' Turnbull

Last November, at the APEC regional summit in the Philippines, President Obama reportedly chided Turnbull for failing to notify Washington ahead of time about leasing the Port of Darwin to China's Landbridge Group for 99 years.

"Let us know next time," Obama said, according to the "Australian Financial Review."

Darwin lease to Chinese firm

Turnbull said Australia's Northern Territory regional government had already done the right thing by getting clearance from Australia's federal Department of Defense for the lease.

At the time, Australian opposition Labor spokesman Stephen Conroy said Washington had had a right to prior notification, particularly as Landbridge allegedly had links with China's People's Liberation Army.

Darwin is also the terminus for a critical underwater data cable.

ipj/jil (AFP, Reuters, dpa)