Yingluck says Thai officials are still studying the merits of entering into talks to join the free-trade group, The Bangkok Post reported Saturday. Certain factions in the country oppose membership -- fearing its potential impact on trade, investment and intellectual property rights -- and intended to protest against it when Obama arrives Sunday afternoon, the newspaper said.
"A number of parties have expressed concern about Thailand's participation in the TPP," Yingluck said.
"No agreement has been made. We are only expressing interest in studying the details and the pros and cons. There will be no talks on this issue with President Obama."
She said Cabinet and parliamentary approval would be needed before any negotiations could begin.
Led by the United States, the trade group includes Singapore, Australia, New Zealand, Chile, Peru, Malaysia, Vietnam, Brunei, Canada and Mexico. Japan and South Korea are considering entering whether to join.
U.S. Secretary of State Hillary Clinton, speaking in Singapore, issued an open invitation to other Asian nations to participate, as well, including China, the Post said.
"For the first time in modern history, nations are becoming major global powers without also becoming global military powers," Clinton said. "We welcome the interest of any nation willing to meet the 21st century standards of the TPP -- including China," she said.