Closer military cooperation will mark the new Australia New Zealand United States (ANZUS) military pact between the Aussies and the Americans and possibly a state visit from U.S. President Barack Obama later this year, according to officials of both nations.

Senior defense and military heads from Australia and the United States are in San Francisco to revisit the six-decade-old mutual defense treaty that requires the signatories to help out each other in the event of hostile attacks.

As a way adjusting to new forms of threats, both countries have indicated that cyber attacks will now be covered by the treaty, which officials are expected to amend following the security conference.

"We will be releasing a joint statement saying that the ANZUS treaty applies to cyber space," one unnamed U.S. official was quoted by Reuters as saying.

That hint was backed by U.S. Defense Secretary Leon Panetta, who said on Wednesday that America treats spectre of cyber attacks with seriousness.

"We're all going to have to work very hard not only to defend against cyber attacks but to be aggressive with regards to cyber attacks as well ... and the best way to accomplish that is not only on our own but by working with our partners." Panetta told the Agence France-Presse (AFP).

America has been highlighting its grave concern on the silent but severe cyber attacks launched by foreign intelligence agents, which the U.S. Pentagon said had successfully pilfered some 24,000 files from defence contractors this year alone.

Such massive data theft has prompted the U.S. military to declare earlier that continued cyber attacks could someday trigger proportional response, with then Defense Secretary Robert Gates not ruling out a possible military strikes on identified hackers.

Apart from its planned collaboration in combating cyber attacks, both countries are exploring the possibility of increasing the frequency of their joint military training exercises, with the likelihood that Australia will allow greater access of its military facilities for U.S. troops.

The move, according to a U.S. official will refocus America's long-time involvement from the Korean Peninsula to the southern parts of the Asia-Pacific region.

"We are looking to enhance our presence in Asia, not decrease it. And Australia would be part of that," the defense official told Reuters.

New Zealand is part of the military alliance but has opted to remain uninvolved since 1985.