|"I don't know which word is stronger, deadlock or stalemate ... The strike continues"|
Abdulwahed Omar, Nigeria Labour Congress
The strike has paralysed trade in Nigeria, the world's eighth largest exporter of crude oil, but oil production and exports have so far been spared.
The government said it would no longer tolerate street blockades by union members, setting the stage for a more hostile face-off with workers.
Babagana Kingibe, the government negotiator, said: "We have not made sufficient progress to enable a resolution of the ongoing strike.
"Government will now consider all other options which it had so far been reluctant to apply to ensure that labour laws are fully respected."
Unions stepped up threats in the hope that the government would fully reverse its increase in the price of petrol.
The government has offered to cut the price by five naira, along with other concessions, but the unions want the price brought back down by 10 niara (eight cents).
The dispute has been the first major challenge for Umaru Yar Adua, the new president, who inherited the unpopular price increase from Olusegun Obasanjo, his predecessor.
Kingibe said the government had overlooked the fact that union members had chased workers from offices and barricaded streets and fuel depots, but that was now to change.
"Government will put every measure in place to ensure that citizens who want to exercise their fundamental rights to go to work will do so without molestation and that filling stations and depots are secured," he said.
Crude oil futures in London, which have been supported by fears of a disruption in Nigerian supplies, rose six cents to $70.28 a barrel.
The general strike was preceded by one by tanker drivers that caused nationwide fuel shortages. Public transport has been affected and most filling stations no longer have fuel.
Analysts say Yar Adua's handling of the crisis has been poor.
His defence of Obasanjo's price increase has reinforced popular belief that Yar Adua was under the influence of his predecessor, who picked him to make him president.
Having offered concessions that were rejected, Yar'Adua gave himself little room to manoeuvre.
|Yar Adua may have left himself little room for|
manoeuvre after offering concessions to unions
Unions had threatened to withdraw key staff from the oil export terminals on Thursday, but ship agents and oil officials said exports went ahead normally.
Peter Akpatason, head of the NUPENG oil union, said the order had been given to withdraw, but he did not know whether it had been fully effective.
Oil companies have contingency plans to sustain essential operations using non-unionised staff, but these measures can only keep oil flowing for a few days, experts say.
Nigeria is a leading crude producer, but virtually all of its petrol is imported due to years of corruption, mismanagement and violence that have left refineries inoperable.