Officials in Canberra have given a cautious welcome to a decision by the Association of Southeast Asian Nations to let Australia join a regional summit. The invitation, however, would require Australia to sign a regional non-aggression pact - something Canberra says would conflict with its 54-year-old defense treaty with the United States.

The door appears to be open for Australia to attend this year's inaugural East Asian Summit in Malaysia. There is, however, a significant catch. Participation in this key regional meeting is conditional on Canberra signing a non-aggression treaty with the Association of Southeast Asian Nations or ASEAN.

Australian Foreign Minister Alexander Downer would not say if Australia would agree to that condition but hinted that it probably would not.

Just last week, Prime Minister John Howard said his government would not sign such an accord.

Mr. Downer said Tuesday he is confident that if Canberra does not ratify the treaty, it would not automatically be excluded from the East Asian Summit.

The summit, planned for December in Kuala Lumpur, would bring together officials from the 10 ASEAN nations with Asia's economic powerhouses - China, Japan and South Korea. Australia, India and New Zealand all have expressed interest in attending the gathering, which is widely seen as a potential precursor to a European Union-style East Asian Community.

In Canberra, the opposition Labor Party is unimpressed with what it sees as the government's indecision. Labor's foreign affairs spokesman Kevin Rudd says it is vital that Australia is invited to the Kuala Lumpur summit.

"It would be a second-class outcome for Australia if we had to wait for another year or so for Australia to be admitted to a summit next year or in the years beyond," said Mr. Rudd.

Labor wants the government to sign the non-aggression treaty, pointing out that both Japan and South Korea have done so while maintaining strong alliances with the United States.

The non-aggression treaty forbids signatories from using violence to settle conflicts in Southeast Asia.

This conflicts with Australia's policy of pre-emptive strikes on terrorist threats. The Howard administration says it will attack to halt such threats in neighboring countries with or without the support of the other country's government.

ASEAN is an influential 10-nation regional grouping comprising Brunei, Cambodia, Indonesia, Laos, Malaysia, Burma, the Philippines, Singapore, Thailand and Vietnam. Australia, like the United States, China and several other countries, takes part in some ASEAN gatherings each year.