Libya's oil production has now reached 560,000 barrels a day, the country's oil head said Wednesday, more than one-third of its prewar crude output of 1.6 million barrels a day.

Speaking to Dow Jones Newswires, Nuri Berruien, chairman of
Libya 's National Oil Co., said the country's oil production was now 560,000 barrels a day, following the resumption of Repsol YPF SA's (REP.MC) giant Sharara field last week.

Most of
Libya 's oil production shut down when the civil war erupted in February, leading to Col. Moammar Gadhafi's toppling in August and his death last month.

But its recovery has surprised most observers, including the authoritative International Energy Agency, which had said the country's oil production would be no more than 400,000 barrels a day by the end of the year.

One key hurdle, however, remains the Es-Sider terminal, the gateway for about a third of
Libya 's prewar exports.

Repairs at Es-Sider are "going to take minimum one month," Berruien said, a view consistent with previous plans to ready the oil port early December.

Berruien said "Es-Sider is the bottleneck" for resuming production at the 350,000 barrels-a-day Waha Oil Co., whose partners are Marathon Oil Corp. (MRO), ConocoPhillips (COP) and Hess Corp. (HES).

Speaking to analysts on a conference call Tuesday, Marathon Oil Executive Vice President Dave Roberts said the company's
Libya output is unlikely to resume soon as it needs to repair some equipment.