State-controlled PTT has studied the possibility of investing in central Vietnam for more than four years and had aimed to start construction this year in partnership with Saudi Aramco, the world's biggest oil producer.
The complex, including a 400,000 barrel per day refinery and an olefins and aromatic petrochemical plant with annual output of 5 million tons, would help to meet Vietnam's domestic demand for oil products and boost its exports.
Vietnam completed a leadership transition in April, when parliament approved a 27-member Cabinet charged with reforming an economy that has grown rapidly but remains dogged by public debt and privatization problems.
Chansin Treechuchagron, PTT's Senior Executive Vice President for petrochemicals and refining, said the company will delay the project and review investment at the end of the year.
"As the situation has changed we should also be prudent in terms of Vietnamese investment," Chansin said, adding that PTT would need state endorsement of the project.
The plan is for PTT and Aramco to each own 40 percent of the project in Binh Dinh's Nhon Hoi economic zone, with the Vietnamese government holding the remaining 20 percent.
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