Vietnam's Thach dangles hope of Kampuchea dialogue

The bustle and speculation that surrounded Vietnamese Foreign Minister Nguyen Co Thach's visit to several neighboring Southeast Asian nations has subsided, but activity continues behind the scenes.

Vietnam hints at a little more flexibility, Prince Sihanouk sends messages to Hanoi, and the new anti-Vietnamese coalition quietly receives aid.

Mr. Thach's visit to Singapore, Malaysia, and Thailand late last month was a masterly demonstration of how to make a little go a long way: He offered no new proposals, made no new concessions, but in an unexpected display of openness and friendliness apparently convinced the Thais that a dialogue with Hanoi over Kampuchea (Cambodia) really offered some hopes of success.

Some of Thailand's partners in the Association of Southeast Asian Nations (ASEAN), Singapore at their head, tried to temper this optimism at the foreign ministers' meeting that followed close on the heels of the Thach visit. Much of the brief meeting seems to have been devoted to stressing that the Vietnamese had not really changed their position over Kampuchea.

At the end of the meeting the ministers expressed their willingness to continue the dialogue with Hanoi. But, as a senior ASEAN official remarked recently, ''Some are still more optimistic than others.''

One point some ASEAN countries would like to examine further is the Indochinese foreign ministers' call for a regional international conference on regional issues.

Unlike ASEAN's longstanding proposal to settle the Kampuchea issue by means of a United Nations-sponsored conference, the Indochinese conference would not be under UN auspices. It would look at Southeast Asian security in general.

After originally saying bluntly that Kampuchea would not be on the agenda of a meeting, the Vietnamese are hinting at a new flexibility: A senior Hanoi official reportedly told a visitor recently that ''of course'' Kampuchea would be discussed at the proposed conference.

Another key actor in the Kampuchean conflict, Prince Norodom Sihanouk, the head of the new coalition, also seems to be intrigued by the Vietnamese conference suggestion. A representative of the prince recently told a Hanoi-based diplomat that, had the prince known about the Vietnamese proposal earlier, he would not have joined the coalition. At the end of the talk the prince's representative reportedly asked the diplomat to convey the prince's words to the Hanoi government.

Whether this was a genuine Sihanouk overture to Hanoi or a princely red herring, only time will tell.

The monsoon rains that, by hindering military operations have allowed the two sides to sound each other out over the last few months, will dry up toward the end of October. By then the coalition government of Kampuchea will have to be able to defend itself against any offensive the Vietnamese might throw at it. So far the Chinese seem to have supplied the bulk of weapons to both communist and noncommunist members of the coalition.

Chinese officials reportedly told visitors to Peking recently that the People's Republic of China had provided Prince Sihanouk with 3,000 guns, and would provide another 2,000 if the prince could raise the men.

Sihanouk's former prime minister, Son Sann, the officials said, had received 6,000, with provision for another 4,000 later. This would seem to fill most of the basic needs of the two noncommunist coalition members.

Peking has not indicated how much it is giving the Khmer Rouge. ''Probably a blank check,'' an ASEAN diplomat suggested.

Although ASEAN officials sometimes say they want to build up the noncommunist members of the coalition to the point they can do without the Khmer Rouge, ASEAN countries are rather coy about admitting they are aiding the anti-Vietnamese forces militarily. ''Frankly,'' a hard-liner remarked, ''it's none of your business.''

But late last year Singapore, which has its own modest arms industry, reportedly gave some weapons to Son Sann.

''Each country makes its own decision about military aid for the coalition,'' a senior ASEAN official explained. ''And it doesn't even have to inform the other members. But I think that at the very least Singapore and Malaysia are giving the noncommunists money to buy arms.''