The head of Thailand's day-old military junta pleaded today for public cooperation to have the kingdom from becoming "the next domino" in Southeast Asia.

Adm. Sangad Chaloryu said that while Thailand wants to avoid "the ideology of the other side," this latest in a series of juntas is prepared to "meet and negotiate" with its Communist neighbors - Vietnam, Cambodia and Laos.

"If everyone cooperates and does the right thing," he said, "our nation will survive. Many people have been worried that our country would be the next domino. But the Thai people want to have freedom without foreign influence."

In recent months, Cambodian armed units have attacked Thai border villages, and there have been reports of large scale buildups by Vietnamese units near the border with Laos.

A number of senior military officiers have expressed concern of late that former Prime Minister Thanin Kraivicren's rigidly anti-Communist policies were contributing to potential conflicts with the Communists.

An oddity of Thanin's civilian, coalition government, which the armed forces installed a year ago and dismissed last night, was that it was less flexible regarding Communism than the armed forces.

Sangad, the nominal head of the 24 member Revolutionary party of top military abd police officers, reassured the country that political activity would be allowed to resume "soon" and that elections would be held next year. A new constitution would be drafted within a year, he said.

The admiral, who was defense minister in Thanin's Cabinet, and the military supreme commander, Gen. Kriangsak Chammanand, told reporters that one of th most pressing reasons the junta removed Thanin was that foreign investment had stagntted during his year in office.

Kriangsak, whon office.

Kriangsak, whom some Western diplomats believe is the real power in the Junta, said the new government would move swiftly to eliminate any "unjust laws" regarding foreign investments, so that foreign investors will feel certain" about the future stability of Thailand. The country has gone through seven changes of government in the last six years.

Kriangsak added that Thailand would seek foreign cooperation in developing its own arms production industry.

The two officers said that policies would be administered by a National Administrative Committee made up of academic and other expert, they hinted that one or more of Thanin's Cabinet ministers might be recalled to participate in the committee. Some observers believed that former Foreign Minister Upadit Pachariyangkul would be the foremost of these.

Kriangsak praised Upadit for his recent spadework at the United Nations in making contacts with the foreign ministers of the three Indo-chinese Communist states.

"We want to be friends" with Thailand's Communist neighbors, Kriangsak said. "Mr. Upadit contacted them at the U.N. and the results were good. They're willing to meet the negotiate and we'll follow that policy."

Kriangsak said the junta is particularly interested in reaching an accord for commercial airlines flying inand out of Thailand to overfly Vietnam.