BSR chairman Nguyen Hoai Giang said the Japanese contractor JGC is working on the refinery's expansion plan, which is expected to be submitted to the Prime Minister for approval next month.

The refinery, which is operated by Binh Son Refining and Petrochemical Co (BSR) and located in central Quang Ngai Province, resumed operations at full capacity on July 14 after the second major maintenance that lasted 56 days.

Giang said that about 4,000 experts, engineers and workers, including 400 foreigners, are involved in the overhaul.

Several major technical flaws are fixed during the process, and the single-point mooring (SPM) at the refinery is upgraded, enabling it to receive oil tankers of up to 150,000 tonnes. Previously it could only accommodate 100,000-tonne tankers.

By the year-end, the refinery plans to churn out about 2.6 million tonnes of products, contributing VND12 trillion (US$564 million) to the State budget.

Starting commercial operations in 2010, the refinery has supplied over 26 million tonnes of oil, petrol and gas products until now, meeting 30% of the demand for petrol nationwide.

In 2013, it produced 6.6 million tonnes of petroleum products, 17% higher than its set target, and gained over VND154 trillion (US$7.3 billion) in revenue and VND2.9 trillion (US$138 million) in profit. It also contributed VND28.4 trillion (US$1.3 billion) to the State budget.