The private sector is calling for a quick and clear stance from the government on the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP).
Companies cited foreign investors who have already invested and are interested in further spending in Thailand, though they are waiting for the government's decision on participation in the pact to determine future action.
"We're inundated with inquiries from foreign investors about the government's stance on participation in CPTPP," said Sanan Angubolkul, vice-chairman of the Thai Chamber of Commerce. "But right now we cannot provide them any clear answers."
The cabinet agreed on May 26 to set up a panel to consider whether Thailand should sign up to the Asia-Pacific trade agreement, amid widespread concerns that doing so could harm vital areas of the economy.
The cabinet shelved a decision on membership in April after stiff opposition from politicians, civil society groups and prominent social figures who said it would hurt the economy, particularly the agricultural and healthcare sectors.
Mr Sanan said a CPTPP working panel of the Joint Standing Committee on Commerce, Industry and Banking has already completed its own study of the pact and its impact and is scheduled to propose to the committee this week its stance on whether to support government participation in the pact.
"The working panel has brainstormed with all parties to ensure the best benefits to the country," he said. "We've studied the pros and cons, as well as the readiness of Thai production and business sectors covering trade, investment and issues of concern."
Mr Sanan said key areas of concern include the import tariff waivers on 99% of all export product items; government procurement that gives equal rights to foreign operators; foreign labour protection and intellectual property, particularly compulsory licensing for patented medicines, such as those for HIV and cancer; International Union for the Protection of New Varieties of Plants regulations; and Thai plant development and genetically modified organism controls.