(Adds Australian foreign minister comments)

SYDNEY, Sept 5 (Reuters) - The United States is giving Australia more access to top-secret American military technology under a new defence cooperation treaty signed on Wednesday.

President George W. Bush and Australian Prime Minister John Howard signed a defence trade cooperation treaty "that will strengthen our already robust alliance", a White House statement said.

"Good job," Bush said as he shook hands with Howard after the signing at Howard's office in Sydney.

Bush told a news conference the treaty would help "transform our forces better, share technology better, and frankly enable our private sectors to work together to develop new defence capabilities to defend ourselves".

Howard also said the two countries would explore enhancing defence cooperation in four other areas; humanitarian and disaster relief, joint military training, intelligence surveillance and reconnaissance and military exchanges.

"I am very confident there will be further and very significant enhancement of an already very close relationship," he said.

Howard said Australia, which has 1,500 troops in and around Iraq, had no closer ally than the United States.

But Australia has long complained of U.S. restrictions on the use, manufacture and repair of top-secret U.S. weapons technology and information because of Washington's concerns about keeping the information secure.

The countries are negotiating the A$16 billion ($13 billion) sale of advanced F-35 Joint Strike Fighters, while the U.S. recently agreed to Australia buying 24 FA-18F Super Hornet fighters for A$6.6 billion.

Australia is also buying U.S.-built cruise missiles and airborne early warning aircraft for its air force and sophisticated radars for a new fleet of destroyers.

"I think one of the very significant things in this potential (deal) is the arranging for greater access for the Australian military, in its purchase of military hardware, to classified and secret technical information about weapons systems and operations," U.S. ambassador to Australia Robert McCallum told Australian television this week.

The development, he said, would allow Australian and U.S. forces to work more closely together on joint military operations stretching from the Middle East to the Pacific.

Australian Foreign Minister Alexander Downer said the pact would benefit Australia's defence industry.

"This is just another building block in the strong defence relations between Australia and the United States, a relationship that frankly works very much in Australia's national interest," he said.

AlertNet news is provided by