Secretary of State Alexander M. Haig, Jr. pledged today that the United States would "shore up those who are under threat and danger" in Southeast Asia and elsewhere, as fire of this region's mpm-communist states concluded two days of talks centering on the Vietnamese occupation of Combodia.

"You can indeed be confident that there is a new American, an America that understands that it must once again bear its burders that history has place on our shoulder, to lead and to shore up where necessary," Haig said in an exchange of toasts with Philippine President Ferdinand Marcos on the second day of a visit here.

He said that although this "hasn't been too necessary in this area," the United States was prepared to "shore up those who are under threat and danger and in the front lines." He added, "You are going to find America with you not in a dominating way, not in a pro forma way, but in a true partnership."

Haig did not elaborate, and the propsect of some U.S. role in providing military aid to noncommunist Cambodian groups fighting the Vietnamese remained clouded by equivocal, sometimes apparently contradictory, U.S. statements.

In a speech Tuesday to the American Club of Peking, Assistant Secretary of State for East Asian Affair John Holdridge appeared to rise just such a prospect in discussing efforts to bring about a withdrawal of Vietnamese troops from Cambodia.

We will seek if we can to find ways to increase the political, economic and, yes, military pressures on Vietnam, working with others in ways which will bring about, we hope, some change in Hanoi's attitude toward the situation," Holdridge said, according to a partial text released today by U.S. officials.

The officials insisted, however, that Holdridge was not signaling any change in the U.S. policy of providing only "political and humanitarian support" for the noncommunist Cambodian resistance to the Vietnamese occupation.

"The whole question of a military option is simply not relevant for us right now," one of Haig's aides said. He added, however, that the United States "won't rule out in the future any option." For now, he said, Washington was continuing to seek a "political solution" to the Cambodian issue.

Nevertheless, news of Holdridge's statement was welcomed by some Asian diplomats here who interpreted it as indicating U.S. willingness to give the noncommunist Cambodians the kind of increased material support they have long sought from Washington.

One foreign minister attending the conference of the Association of Southeast Asian Nations (ASEAN) said he found Holdridge's remarks "quite encouraging" on the prospect of U.S. military aid for the noncommunist Cambodian resistance.

But he and other ASEAN officials were much less enthusiastic about the possibility of American arms sales to China which also opposes the Vietnamese presence in Cambodia.

U.S. officials accompanying Haig tended to discount any ASEAN objections on this issue.

"Given the fact that any arms decisions would focus on defensive capabilities, we could manage any adverse reaction," one official said. However, the ASEAN foreign minister expressed concern not so much that U.S. weapons might eventually be used against noncommunist Southeast Asian countries, but about the U.S. policy's implications for the future.

He said he feared it might mean Washington was prepared to let China play a bigger role in the region, leading to future Chinese dominance over the whole area.

"We can never forget that China is communist," the official said. He said ASEAN countries remained troubled by latent -- though diminished -- Chinese support for communist insurgent groups in several states.

Another ASEAN diplomant said he did not know whether the U.S. decision would become a "contentious issue" when Haig confers with ASEAN delegations here during the next two days.He said that both Indonesia and Malaysia previously had expressed concern about U.S. sales to the Chinese.

"Although the ASEAN countries now see Vietnam as the main threat in the region, in the longer term China could be the main threat," the diplomat said.

In concluding their meeting today, the foreign ministers of the Philippines, Thailand, Indonesia, Malaysia and Singapore reiterated ASEAN's appeal in Vietnam to join an international conference in New York set for next month to discuss Hanoi's occupation of Combodia.

The ASEAN communique called for the withdrawal of "all foreign armed forces" from Cambodia under the supervision of U.N. peacekeeping forces and for the disarming of all Cambodian factions immediately after such a pullout.