Chrysler Corp. executives are holding talks with Mitsubishi Motor Corp.'s Thai affiliate on plans to export compact cars to the United States.

The talks coincide with Chrysler's negotiations for additional shipments of the cars to Canada. The first such shipment was sold out within days of its arrival in Canada.Chrysler President Gerald Greenwald expressed optimism at a meeting with Thai Prime Minister Prem Tinusolanonda that the compacts could eventually be sold in the United States, sources told The Journal of Commerce.

The Chrysler delegation arrived from the United States a week ago Sunday and was joined by representatives of Chrysler Canada, according to Vachara Phanchet, international business manager at MMC Sittipol Co., the local unit of Mitsubishi.

No specific figures were broached at the meeting with Mr. Prem, but an official at Thailand's Ministry of Industry says Chrysler, of Highland Park, Mich., is interested in buying up to 5,000 compacts a month.

Several industry sources, however, doubt the Thai company is technically sophisticated enough for the U.S. market. Exports to the United States must be at least 51 percent Thai content. The compacts MMC Sittipol is supplying to Canada are 33 percent local content.

Sources also question whether MMC Sittipol can meet the volume demand of the U.S. market. The company has only modest production facilities, already strained by the Canadian contract. Any additional output would necessitate either construction or purchase of another factory.

Industry executives speculate that Mitsubishi, which is 24 percent owned by Chrysler, may be planning a major investment in its Thai affiliate to expand capacity and upgrade its technical expertise. Mitsubishi has already announced plans to build a plant in Thailand to produce engines for its export cars.

Thailand's auto exports are underpinned by growing foreign sales of car parts and accessories. Investment applications here by Japanese and Taiwan car-parts manufacturers were strong in 1987, much better than in the rest of the Southeast Asian region.

Thailand is also exporting more motorcycles and parts.