Commercial production had begun from Nov. 14, Nghi Son Refinery and Petrochemical LLC said in a statement, while a source at the refinery told Reuters the refinery was operating smoothly.

The $9 billion refinery is 35.1 percent owned by Japan's Idemitsu Kosan Co, 35.1 percent by Kuwait Petroleum, 25.1 percent by PetroVietnam and 4.7 percent by Mitsui Chemicals Inc.

The 200,000 barrels-per-day (bpd) Nghi Son refinery, 260 km (160 miles) south of Hanoi, offered its first gasoline export cargo in September after receiving approval from the government to begin exporting fuel products.

Nghi Son and the 130,000-bpd Dung Quat refinery, which began production in 2009, are together expected to meet about 70 percent of Vietnam's refined oil product demand.

(Reporting by Khanh Vu; Editing by Sai Sachin Ravikumar)