The oil workers began striking on Tuesday over a disagreement with the government over pensions and a lack of crude supplied to refineries.
Babatunde Oke, spokesman for the white-collar workers' union PENGASSAN, said by text message that "the strike is still on, as no agreement had been reached".
(READ MORE: Effects of oil workers' nationwide strike on Nigeria's oil & gas space)
The workers on strike are only those who work for the state-owned oil firm the Nigeria National Petroleum Corporation (NNPC), not the international oil majors which operate the oil blocks and export terminals.
A senior official in an international oil company said the strike could become a threat if it became more generalised to include workers for private oil companies as well as the government, but there was no sign of that yet.
Another market source said there had been no impact on exports so far, but that a bigger risk might be fuel shortages if tanker drivers refuse to supply gasoline stations with imported fuel that makes up 80 percent of the country's needs.
"The strike is a local issue that will soon be resolved. It has not affected oil production and lifting," NNPC spokesman Ohi Alegbe said by telephone.
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"Equally, (the government) is still supplying PMS (gasoline) to various outlets, that's why we have not experienced any fuel scarcity."