Production has restarted at Eni's largest oilfield in Libya, known as Elephant/El-Feel because of its size, pumping 40,000 barrels per day (bpd), Hussein Abuseliana, field manager at the site said on Saturday.

"Production has been on line starting 10 November. We started with ... 40,000 bpd, because electric power is very limited," he told Reuters by phone.

El Feel pumped 130,000 bpd before the war. Abuseliana said his team began working on oil stored in tanks and later began operating wells.

"We have restarted five wells," he said. Some equipment from El Feel, mainly from the control room, had gone missing during Libya's war, he added.

Eni declined to comment.

Abuseliana said his team was working on getting power back up and running smoothly to increase production. El Feel is adjacent to Spanish oil group Repsol's El Sharara oilfield in the southwestern desert region of Fezzan. El Sharara restarted production last month.

"It is a slow start ... We will try to increase our production gradually," Abuseliana said. "We are missing some devices that need to be found to make our plant function fully ... Control room equipment, devices are missing."

He said the main damage was at the camp and a team was working on restoring accommodation.

"The plant is OK," he said.

As at other oilfields across the country, El Feel was under armed guard, Abuseliana said. Around 20-25 people were working at the site, he added.

The head of Libya's National Oil Corporation (NOC) said this month Libya's oil production had risen to 567,000 bpd. Before the February uprising, Libya was pumping around 1.6 million bpd of which 1.3 million flowed onto the international market but civil war caused a virtual halt in output.

Output will easily exceed 700,000 bpd by the end of this year and will be back to pre-conflict levels by about June 2012, interim oil minister Ali Tarhouni said on Thursday.

Italian oil and gas major Eni, the largest foreign oil producer in Libya before the war, expects to restore by mid-2012 as much as 95 per cent of its oil output in the North African country, its head of exploration and production told Reuters last month.

He said Elephant was not damaged by the war and all facilities were in place. But it remained a risky area and it was still not clear when the output from the field could restart.