Iran currently produces almost 64 million litres (16.9 million gallons) of petroleum a day and imports 12 million litres to meet domestic demand.
In its first phase, the Setareh Khalij Fars (Star of the Persian Gulf) refinery aims to produce 12 million litres of Euro IV-grade petroleum.
The next two phases, scheduled for launch within 12 months, aim to raise total production of Euro IV and Euro V petroleum to 36 million litres a day.
According to the oil ministry's Shana website, Iran's total output will thus exceed 100 million litres.
"Once the two other phases of this refinery enter service, Iran will become an exporter of petroleum products," said Khatam-al Anbia chief General Ebadollah Abdollahi, quoted by Shana.
Construction work started 10 years ago but was slowed by international sanctions, which have been eased by the July 2015 signing of an accord between Tehran and world powers on curbs to Iran's nuclear programme.