US Secretary of State Hillary Clinton arrived in Australia on Tuesday for annual strategic talks, with Prime Minister Julia Gillard describing the two countries as "good mates at every level".

On what could be her final visit Down Under in her current role, Clinton will be joined by US Defense Secretary Leon Panetta for the discussions with Australian counterparts Bob Carr and Stephen Smith on Wednesday.

They are expected to focus on regional security and greater US use of Australian facilities, particularly increased access to a key navy base south of Perth, as the Indian Ocean rim region grows in strategic importance.

The talks follow the arrival of US Marine units to northern Australia this year as part of a US "rebalance" toward the Pacific after a decade of ground wars in Iraq and Afghanistan.

The US military currently has only a limited deployment in long-standing ally Australia, including the Pine Gap Joint Defense Facility spy station near Alice Springs.

The move to station marines - some 2,500 by 2016-17 - represents a significant geo-strategic shift by Washington.

As well as bilateral relations, Gillard said the talks would touch on the war in Afghanistan, conflict in Syria and nuclear issues involving Iran.

"These talks will also deal with discussing what President Obama and I agreed last year about military cooperation between our two countries," she added.

"Last year President Obama and I announced that we had agreed that US Marines would be training on deployment in the Northern Territory. These talks will stocktake that progress and further defense cooperation."

Australia has had an alliance with the United States for more than 60 years, and Gillard described Washington as "the oldest of allies", with which it shared strong strategic, defense and economic bonds.

Since 1951, the Australia, New Zealand, United States Security Treaty, or the ANZUS Treaty, has bound these two countries (far better than ANZUS has bound New Zealand) in military and strategic mutual affection.

A US presence in the Pacific has been the bedrock of Australia's security posture, and in return Australia has participated in every one of the US foreign military adventures, from the Korean Peninsula, through Vietnam into Iraq, the "war on terror" and Afghanistan.

Peter Jennings, executive director of the Australian Strategic Policy Institute, says it will be money or the lack of it in Australia's defense policy that will be foremost in the mind of Clinton and Panetta.

"Based on recent visits to the US, I can confirm that a wide range of current and previous administration officials and others watching the relationship are worried about Australian policy," Jennings said.

"Americans are dismayed that there has been such a quick reversal of Australian defense spending plans from 2009 to now," he said, adding that the US is worried about the tone of Australian commentary, led by analysts like Professor Hugh White, who has championed the concept of shared power within the Asia Pacific by the US and China.

AFP - Xinhua