Essam al-Muntasir, a spokesman at the Zawiya Oil Refining Co., was quoted by the Tripoli Post as saying employees had returned to work and fuel deliveries have resumed from the refinery near Tripoli.
"Employees have gone back inside the refinery and are beginning the process of starting up the machinery," he said. "Fuel tanks are also able to enter and exit the refinery to transport fuel."
The spokesman said Libyan war veterans last week forced the shutdown of the refinery to press for better treatment. Similar demonstrations in early November closed the refinery for two days.
Muntasir told the Libyan news service that the government managed to break up recent protests by offering wounded veterans unspecified concessions.
The refinery is about 30 miles west of Tripoli. Its 120,000 barrel-per-day capacity meets about 40 percent of the oil demand for western Libya.
The Libyan oil sector has rebounded since last year's civil war and is producing around 1.6 million barrels per day, its pre-war level. Leaders said production could surpass the pre-war benchmark as soon as 2015.