A conference between communist and noncommunist nations in Southeast Asia dealing with the war in Cambodia is "not in the cards" despite Vietnamese claims to the contrary, according to Malaysian Deputy Prime Minister Musa Hitam, whose country is chairman this year of the noncommunist group.

Musa, winding up two days of talks with Secretary of State George P. Shultz and other U.S. officials, said such a meeting would be "a fruitless exercise" from the viewpoint of the Association of Southeast Asian Nations (ASEAN) unless there is a change in Vietnamese policy. Musa said no change is in sight.

In mid-October, Vietnamese Foreign Minister Nguyen Co Thach said while visiting the United Nations in New York that meetings between the communist and noncommunist nations would begin soon, based on preliminary discussions he had held with diplomats from Indonesia, Malaysia and other ASEAN countries.

Musa, however, told reporters that the Vietnamese minister's statements had been "a pre-General Assembly exercise . . . a PR thing to say, 'We're not so bad after all.' "

State Department sources said ASEAN countries were offended by Vietnam's alacrity in making public Musa's preliminary discussions in New York about possible future meetings of communist and noncommunist states. The sources said ASEAN diplomats believed, as Musa hinted, that Thach was seeking to affect the annual voting in the U.N. General Assembly about Cambodian issues.

As it turned out, the ASEAN resolution on Cambodia was backed in the General Assembly, 110 to 22. This is a wider majority over the Vietnamese-backed position than in the past.

The Malaysian deputy premier said he placed no special significance on the recent Vietnamese attacks on a Cambodian refugee camp along the Cambodian-Thai border. State Department officials said the attacks beginning last weekend seemed to mark the start of Vietnam's annual dry-season offensive at a much earlier date than in the past.

Musa said that from Malaysia's standpoint the situation in Cambodia is "basically a Kampuchean Cambodian -- Vietnamese problem." This appeared to be a way of placing the difficult and contentious issue on the back burner. In Malaysia's view, Musa said, Cambodia is an issue between communist and noncommunist nations of Southeast Asia only to the extent that Vietnamese forces invade Thailand.

Most of Musa's discussions here centered on Malaysian efforts to deal with the narcotics problem among its populace and in relation to other countries. Malaysia has become a transfer point for narcotics produced in the "Golden Triangle" to its north. Because of increasing drug addiction at home, Musa said, Malaysia has designated drug abuse as "a national security problem."