NORSI, Russia's fourth-largest oil refinery, is likely to restore more than 70% of its gasoline production capacity in the next few days after completion of maintenance at some units, three sources familiar with the work told Reuters.

Lukoil, which owns the refinery near the city of Nizhny Novgorod, some 430 km (270 miles) east of Moscow, last week said that NORSI had halted a unit after an incident.

The outage sparked fears of gasoline shortages across the country and there were media reports suggesting that the government was considering imposing an export ban on the fuel, as it did last autumn.

The sources said the company has restarted a reformer unit and that one of the catalytic crackers is due to reach full capacity in the next few days. Another catalytic cracker remains out of action.

A Lukoil representative was not immediately available for comment.

Industry sources have said there were two incidents affecting the plant's gasoline-producing units in early January. The plant can usually process about 17 million metric tons of oil per year (340,000 barrels per day).

They said the catalytic cracking unit with capacity of 6,300 tons per day was halted on Jan. 4 and that a reformer with daily capacity of 3,000 tons per day suffered an outage on Jan. 7.

"They restored the reformer yesterday, Jan. 18, and they plan to reach full capacity in one or two days," one of the sources said.

Industry sources had said on Monday that the NORSI oil refinery's high-octane gasoline output could be halved after the emergency stoppage at one of two catalytic cracking units.

It's not clear yet when the second cracker will be repaired. Some sources said repair work could last until the end of March. (Reporting by Reuters Writing by Vladimir Soldatkin Editing by Jason Neely and David Goodman)