Oil Terminals Company, a subsidiary of the state-run National Iranian Oil Company (NIOC), says the new storage capacity will help Iran divert seasonal offshore oil into onshore storage facilities.

Construction is expected to take between 18-24 months but it is not known if Oil Terminals Company is hiring international contractors to help build the facility.

"Construction of the tanks will enable the country to raise its storage capacity by 50 per cent," says Mousa Souri, managing director of Oil Terminals Company, according to Iran's official energy news agency Shana.

Souri says that Iran's current level of stored crude in existing tankers is at its lowest level in five years.