Secretary of State Hillary Clinton said the Pacific "is big enough for all of us" as the United States pushes for a more visible military role across the region to counter China.
In a speech at a marine defence hub in the South Australian capital Adelaide, America's top diplomat on Thursday sought to allay fears about Washington's pivot into Asia, which has irked Beijing.
She called Australia an "indispensable" ally and said both Canberra and Washington wanted to strengthen ties with China and other nations in the region, in what she called "the Pacific century".
"These past three days have reinforced for me the indispensability of the US-Australia partnership," she said, a day after annual security and strategy talks between the two nations in Perth.
"We are cooperating everywhere together -- in business, in shipbuilding, from the mountains of Afghanistan to the atolls of the Pacific, to the thriving cities of Asia.
"But I know there are some that present a false choice -- that Australia needs to choose between its long-standing ties to the US and its emerging links to China," she added.
"Well, that kind of zero-sum thinking only leads to negative-sum results."
At the Perth talks, the two governments launched discussions on granting the Americans future access to air bases in northern Australia as well as naval ports, including one in the Indian Ocean south of Perth.
The two sides also announced the United States military would station a powerful radar and a space telescope in Australia to monitor Asian airspace.
It follows the deployment of US Marines this year in Australia's north, a move that has sparked concern in China and other nations, including close Australian neighbour Indonesia.
Clinton said Australia's relationship with the United States should be seen as complementary to its ties in Asia, particularly China which is Canberra's biggest trading partner.
"We support Australia having strong, multi-faceted ties with every nation in the Asia-Pacific, indeed in the world, including China, just as we seek the same," she said.
"And I have said repeatedly, the Pacific is big enough for all of us."
Earlier, Australian Foreign Minister Bob Carr played down scathing comments by former leader Paul Keating that Australia has become too compliant to the United States while neglecting relations with Asia.
Keating, who as Labor prime minister between 1991-1996 championed closer ties with Asia, particularly Indonesia, said the region saw Australia as a client of the United States which tended to fall in with its foreign policy.
But Carr rejected the critique, insisting Australia's foreign policy objectives had not been surrendered to the United States.
"We are in a treaty relationship with the United States because we've got a major task, and that is the security of this continent, a small population, a large continent, an uncertain region, an uncertain world," he said.
Clinton, who was speaking at Adelaide's Techport marine defence hub, the site of much of the work on Australia's new air warfare destroyers and its next fleet of navy submarines, heads to Singapore on Friday.