The Nigeria Labour Congress (NLC) has called on Nigeria's 130-million strong population to stay at home from Monday for a four-day show of force, in protest at petrol price hikes triggered by Obasanjo's deregulation of fuel sales.
Nigeria is Africa's biggest oil exporter and world markets will be watching closely to see if the strike or any associated disorder disrupts supplies, at a time when crude prices are soaring to new highs on an almost daily basis.
Tension within Nigeria was further stoked on Saturday when NLC president and firebrand labour leader Adams Oshiomhole was seized by a squad of officers from the feared State Security Service as he prepared to fly from Abuja to Lagos.
A dispute over what happened next added to the confusion and anger.
The SSS blamed the detention on a "misunderstanding" between Oshiomhole and field officers, and claimed he had been released within two hours.
But NLC leaders branded the arrest an "abduction"; alleged that Oshiomhole had been manhandled, bruised and dragged across tarmac; and told reporters that he had not been released but was being held incommunicado at a secret location.
By Sunday morning Oshiomhole had apparently resurfaced, but union leaders were tight-lipped about where he had been for the missing 24 hours.
"He appeared today, this morning. We've seen him now," said NLC spokesman Owei Lakemfa, refusing to provide further details until a planned news conference, at which Oshiomhole was expected to speak.
"The arrest will not affect the planned action. It shall be total and nationwide," NLC acting general secretary Salihu Lukman said in a statement.
On September 23, pump prices for petrol and diesel jumped by around a quarter, settling at around 55 naira (40 cents) per litre in major cities and reigniting a long-running feud between the union and Obasanjo's administration.
Since the last fuel price strike in June, the second such protest since Obasanjo announced that he was to phase out fuel subsidies, the government has attempted to legislate the NLC out of existence.
Seeking to "democratise" labour law, Obasanjo has pushed through an amendment which will deregister the NLC as Nigeria's main union umbrella group and severely restrict its powers to gather subscriptions or to call strikes.
Meanwhile, a court has ruled that the unions have no right to strike to oppose government policy unless it directly affects pay and conditions.
Nevertheless, the unions are riding high on a wave of public opposition to the fuel price rises, which began in October last year when Obasanjo gave private firms the right to import and sell refined petroleum at market prices.
Fuel deregulation is a key plank in a broader reform programme designed to shake up Nigeria's corrupt public sector, encourage private investment and slim down government, a plan which has won international praise.
But Nigeria exports around 2.5 million barrels of crude every day, and its long-suffering citizens see cheap fuel as a birthright and the only tangible thing that a series of incompetent and brutal governments has ever given them.
With oil prices above 53 dollars a barrel -- and a 2004 national budget based on a predicted 25 dollars per barrel -- many fail to see why the massive projected budget surplus should not rain on them in the form of cheap fuel.
"They have 600 billion naira (4.6 billion dollars/3.7 billion euros) spare, and yet people are continuing to suffer," declared Femi Aborisade, a left-wing opposition leader who was himself held briefly by the SSS on Saturday.
More than three-quarters of Nigeria's huge population live in abject poverty on less than one dollar per day: a proportion which has doubled in the 40 years since oil was first discovered in the country. Disease and unrest are rife.
But Nigeria's internationally respected finance minister, former World Bank (news - web sites) vice-president Ngozi Okonjo-Iweala, plans to save the bulk of the oil windfall to pay down debt and protect against a future collapse in oil revenues.
And Obasanjo argues that the money he will save in abandoning the fuel subsidy would be better spent on primary education, health care and roads.
