CANBERRA, Feb 16: The United States is to build a new military satellite communications base in Australia, the government said on Thursday after three years of secret negotiations between the two allies.

The new base will relay signals and intelligence to US forces in the Middle East and Asia from Geraldton, 400km north of the West Australian state capital Perth.

Australian Foreign Minister Alexander Downer told parliament the base, construction of which will start in months, would help underpin the close Australia-US alliance.

But Greens lawmakers warned it would become a target for extremists.

“It will be hosted in the same basis as all other Australia-US joint facilities and operate on the basis of our full knowledge and our full concurrence,” Downer said.

The United States already has bases at Pine Gap, near Alice Spings, which provides early missile launch warning for Asia and the Middle East, and Northwest Cape in Western Australia, which carries signals to US nuclear submarines in Asia and the Pacific.

There is another facility at Geraldton which intercepts mobile telephone signals and communications from Antarctica to Siberia, siphoning intelligence from Asian countries.

Greens Senator Rachel Siewert said the new base would be a prime target near one of Australia's major cities, Perth, which has a population of around one million.

“We’re virtually talking about a Pine Gap on Perth’s doorstep and I think the people of Perth and particularly the people of Geraldton should be very concerned,” she said.

The minority Australian Democrats said the government was assisting a US defence policy which was “deeply misguided and aggressive”.

The alliance with the US and the war in Iraq are shaping to be key issues in elections this year, with recent polls showing 62 per cent of Australians oppose the government’s handling of the war.

There are around 1,400 Australian soldiers in and around Iraq.

Defence Minister Brendan Nelson said Canberra was in discussion with the U.S. about other facilities, including a link to the US military weather satellite network.

The US has also been given approval to store weapons and supplies in Australia’s north for American forces based in Asia.—Reuters