Oil company officials in Nigeria say a strike called by oil workers is not affecting output.
Long lines of cars formed at filling stations in the Nigerian capital, Abuja, Monday as news of the strike caused concerns of possible shortages.
Foreign oil companies operating in Nigeria, however, said supplies remained uninterrupted as few employees heeded the call to stop working.
Those threatening to strike are senior level employees with the government's department of petroleum resources whose job is to supervise the loading of oil at terminals operated by foreign companies.
The employees, who belong to a branch of Nigeria's largest union, Pengassan, the Petroleum and Natural Gas Senior Staff Association of Nigeria, said they would launch the strike in a dispute over unpaid allowances.
Nigeria is one the world's top ten producers of oil, and threats of a strike raised fears that a stoppage could send oil prices soaring further.
Prices for crude are already at a longtime high due to concerns about a possible U.S. war in Iraq, and an ongoing strike in Venezuela, another leading oil producer.
Nigerian government officials said they were taking measures Monday to prevent an interruption of exports. The government said it was dispatching replacement staff to take over management jobs at terminals and other exporting facilities.
Union employees are threatening to walk off their jobs at facilities across the country if the government does not bow to their demands by Wednesday.