Fuel was sold on the black market during a previous strike
Nigeria's
two main oil workers' unions have begun a nationwide strike,
threatening to hurt the output of Africa's largest oil producer.
BBC reporters say long queues have formed at many petrol stations.
The unions, Pengassan and Nupeng, said the strike would continue until the government addressed its concerns.
These include the adoption of the delayed Petroleum Industry
Bill, aimed at overhauling the sector and maintenance work on oil
refineries.
The unions frequently go on strike or threaten to strike.
This time, the two unions were initially demanding the
reinstatement of representatives who had been dismissed by oil
companies, but now their list of complaints has grown.
They are now protesting that the government has allowed
Nigeria's oil refineries to fall into disrepair and that the poor state
of the country's roads is hindering the transport of oil.
They are also asking for the price of petrol to be reduced and oil theft to be stopped.
"We've commenced the strike. It will affect oil production,
since all operations are on strike," Pengassan chief Babatunde Oke told
Reuters.
However, an oil executive said the strike was not expected to
affect output, because it would require the co-operation of large
numbers of workers at production sites who would be unwilling to go that
far.
"It's very difficult to shut them down, and once they do, it
would take them a week to get them back up. They never do it. That's the
last thing anyone wants," an oil executive told Reuters.
The BBC's Will Ross in Lagos said most of the unions' demands seemed "unrealistic, especially with an election looming".
"The refineries are not suddenly going to be fixed because of
this strike. Some oil industry watchers suggest the unions are simply
trying to force the government to pay them off and get a hefty Christmas
present," he added.
A strike in September had little impact on oil production.
Many Nigerians, whether Christian or Muslim, travel home over
the Christmas and New Year holidays and so they are stocking up on fuel
now, in case of shortages in the next couple of weeks, analysts say.