Yemen's oil and gas pipelines have been repeatedly attacked by Islamic militants or disgruntled tribesmen since anti-government protests created a power vacuum in 2011, disrupting exports from the small producer.

The country's main Maarib oil pipeline carried crude to the Ras Isa export terminal on the Red Sea coast until a spate of attacks in late 2011.

Ongoing tension between the government and tribal leaders in the sparsely populated country is preventing one of the government's biggest revenue sources from being reopened.

"The technical teams fixed all the holes that were made by the tribesmen in the pipeline through the past year and half, but they could not fix two holes in the Al Shabwan area because the tribesmen would not grant the teams entry," the Oil Ministry official told Reuters.

The tribesmen want the government to prosecute whoever is responsible for the death of the deputy governor of Maarib province who was apparently killed in a US drone strike more than two years ago, the official said.

He did not give a date when oil exports could be resumed but said it would take time for the issue to be resolved.

Earlier this month, Yemen's Oil Minister said the country would resume oil exports from Maarib this week, ending a lengthy outage which has cost the impoverished country up to $15 million a day in lost revenues.