The National Iranian Oil Company (NIOC) has confirmed that it is to close a major unit at its largest crude oil refinery at the end of October for general maintenance work.

At present, while Iran is the fourth-largest exporter of oil in the world, it is lacking in refining capacity, forcing its government to rely upon imports of gasoline, a situation Tehran is looking to address as relations with the West remain shaky.

As such, NOIC is investing several billion pounds on upgrading its domestic refining sites as it aims to increase the levels of oil being processed from the present level of 1.6 million barrels per day to 3.0 million barrels per day.

By shutting down the part of the Shatt al Arab plant for between 30 and 40 days, ministers hope to boost capacity in the long-run, though the move looks set to ensure the government's current gasoline rationing policy remains in place for the foreseeable future.

"Yes, they will start this maintenance in October sometime, when the weather is cooler," a NOIC official confirmed to Reuters.

Earlier this year, Iranian officials confirmed that work has started on seven new oil refineries across the country, with a combined cost of around £23 billion.

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