Refiner Idemitsu Kosan Co., which has shut down 23 percent of processing capacity since 2003, will boost crude and oil products trading in Singapore as it expands its business overseas.

The company plans to invest $9 billion with its partners to build a 200,000 barrel-a-day refinery in Vietnam to capture increasing local demand amid falling consumption in Japan. The Nghi Son plant is scheduled to begin operation in 2017.

"We have to enhance the function of the Singapore office because we will have a new refinery in Vietnam," Takashi Tsukioka, president-designate of the firm, said in a May 31 interview. "Countries such as Myanmar, Laos and Cambodia are also expected to develop further."