The United States will position more troops in northern Australia under a new bilateral military agreement that will eventually see 2,500 U.S. forces in Australia, Prime Minister Julia Gillard said on Wednesday after talks with U.S. President Barack Obama.

The agreement will not include a permanent U.S. base in Australia, but will see more forces transit through Australia, offering closer access to the South China Sea than America's bases in Japan and South Korea.

Australia is a staunch U.S. ally and Obama's trip is timed to celebrate the 60th anniversary of the ANZUS military alliance, which is the cornerstone of Australia's defence strategy.

Obama will address Australia's parliament on Thursday, where he will focus on the United States in the Asia-Pacific region.

(Reporting by James Grubel and Caren Bohan)