Union leaders said there was nothing government could now do, short of immediately slashing pump prices, to avert a shutdown from midnight on Tuesday which would paralyse economic life across a nation of 130 million people.
The strike could also have global economic consequences if it forces already soaring world oil prices any higher, and observers here fear it could trigger further bloody unrest in the frequently unstable west African giant.
"The strike plan is on course. We have given our members instructions to shut down. Both the upstream and downstream sectors will be affected," said Mojibayo Fadakinte, general secretary of the white-collar oil union PENGASSAN.
The union's blue-collar counterpart, NUPENG, said that it would stop loading crude oil at terminals from Wednesday, threatening to halt exports that account for 95% of the foreign earnings of Africa's biggest oil exporter.
Both Nigeria's main union umbrella bodies - the workers' Nigeria Labour Congress (NLC) and managers' Trade Union Congress - back the strike.
NLC national mobilisation officer Denja Yacqub said: "We are mobilising everybody to join the strike: the banks, the oil workers, the transporters, civil society, students and traders."
"We are not negotiating with any government or anybody. The time for talks or negotiations has passed," he said.
President Olusegun Obasanjo's spokeswoman and officials at the labour ministry refused to comment on the forthcoming strike, but the chairman of the ruling People's Democratic Party said labour's position was "too extreme".
"We are not negotiating with any government or anybody"
Nigeria Labour Congress official
Long queues snaked through the crowded streets of Lagos towards markets and filling stations, as residents sought to stockpile in advance of the strike. And while there was annoyance at rising prices, most said they supported labour.
On 28 May, Nigerian service stations raised prices from 41.7 naira per litre (around 30 cents) to between 50 and 55 naira.
The price is still low by world standards but it marks the latest in a series of steep increases in an oil-rich country whose impoverished citizens once regarded cheap, subsidised fuel as a birthright.
Since Obasanjo came into office in May 1999, oil prices have risen at least five times.