Up to 1,200 workers at the Grangemouth site in Scotland will walk out on Sunday for two days in a row over pensions, forcing the closure of the site.
The strike could hit the Forties pipeline, which delivers almost one third of the UK's daily oil output, it was disclosed last night.
Oil is piped ashore on an adjoining site but relies on steam from Grangemouth to function.
Energy minister Malcolm Wicks said today that the pipeline was a "crucial" piece of infrastructure but he added that at the moment there was no agreement between the Unite union and Grangemouth owners Ineos about how it could be affected.
Mr Wicks said he understood a decision would be taken in the next 24 hours on whether the pipeline, which is run by BP, will have to be closed down because of the strike.
Downing Street today urged the two sides to get back round the negotiating table to resolve the dispute.
"We believe that this is a dispute that should be resolved," a No 10 spokeswoman said. "We are encouraging both sides to get round the table and bring about a resolution based on common sense."
The spokeswoman said that while the industry believed there were sufficient stocks to keep forecourts re-supplied, the Government was urging motorists not to try to buy extra fuel.
"Increasing demand could potentially cause problems for those who need fuel," she said.
The offshore oil industry body Oil and Gas UK warned that closing the pipeline could cost an estimated £50 million a day in lost production, with the Treasury taking half that hit.
Mr Wicks, speaking on BBC Radio 4's Today programme, said petrol supplies across the UK should not be a problem, but he admitted that some motorists could be hit.
He said he could not guarantee that every garage and every forecourt would have petrol every time motorists arrived to fill up.
"I cannot guarantee that every garage forecourt will have petrol at that precise moment.
"I hope the vast majority of people are sensible about this. They might have to be patient. People will have to be sensible and rational."
Mr Wicks said later: "There are short term stock outs occurring at some filling stations in Scotland, but the petrol industry is confident that they can continue to resupply from stocks and imports, even in the event of this strike going ahead.
"This is not a supply issue, it is a logistical issue and the industry is responding well. What is vital is that Ineos and Unite get back to the negotiating table to sort this dispute out and to avoid any further inconvenience in Scotland."
Mr Wicks admitted that the Grangemouth site would not immediately re-open following the two-day strike, and conceded that the dispute had "long-term implications".
He urged both sides to resume peace talks in a bid to resolve the dispute over the closure of the Ineos final salary pension scheme to new workers.
Governments on both sides of the border have tried to reassure the public that there are enough supplies of fuel to cope with the strike.
Scotland's First Minister Alex Salmond said there were enough supplies of petrol and diesel to last well into May.
Motoring organisations have urged drivers not to panic buy because if every motorist filled up their car at the same time there would be fuel shortages.
A mass meeting will be held at Grangemouth later today addressed by Tony Woodley, joint General Secretary of Unite.
He will bring the workers up to speed on details of negotiations which broke down earlier this week.
Grangemouth's general manager Gordon Grant said fuel supplies should last throughout the strike as long as motorists did not panic.
"We have been working very hard to import supplies and have been very successful.
"We believe we can supply fuel, if people just buy at their normal rate."
Mr Woodley repeated the union's warning, first disclosed by PA yesterday, that the dispute could escalate unless the deadlock over pensions was resolved.
He told BBC Radio 4's Today programme that following the two-day strike there would be a "pause of peace".
But he said that if the company remained "intransigent" then an escalation of the dispute was "absolutely inevitable".
Mr Woodley said there was "no justification" for the planned pensions changes and he accused the company of being "hell bent" on trying to reduce workers' pensions.
Asked about the likely impact on fuel supplies Mr Woodley replied: "We understand the seriousness of the situation. It is extremely serious - that is why Unite has been behaving responsibly. We have made sure the plant and equipment is in a state to start up extremely quickly and we have made sure there is emergency cover for the emergency services."
Mr Woodley accused Ineos of "going through the motions" during the two days of peace talks this week at Acas.
Mr Woodley will make clear at today's mass meeting that the union intends to "steadfastly support" the workers involved in the dispute.
Unite accused Ineos of refusing to back down over closing the "well funded" pension scheme to new workers.
"The company has already moved to reduce its contributions to the scheme and has made other detrimental pension changes for employees, including introducing financial penalties for early retirement.
"These changes were made against the wishes of the pension scheme members and breached a six-month consultation.
"Unite has left the door open to negotiations and says if the company is willing to negotiate in the proper sense, it will respond.
"The Grangemouth workers have guaranteed safety and emergency cover for the duration of the dispute," the union said in a statement.
James Withers, chief executive of NFU Scotland, said farmers could face major difficulties if fuel supplies run dry.
He told BBC Radio Scotland there was a mood of "real concern" as farmers were told by suppliers that there would be difficulties with their deliveries.
He said farmers were in a "crunch period" of the year at the moment, with activities such as planting potatoes, sowing crops and lambing going on, which all demand fuel.
He said: "Ultimately, if they can't get the fuel, they cannot do those jobs."
There are also concerns over animal welfare if farmers cannot get out on their quad bikes to check their stock, or feed deliveries cannot get through.
He told the Good Morning Scotland programme: "It is causing concern and that can have a real emotional impact on individuals. I think it's fair to say that we've not hit crunch point just yet and people are listening to the Scottish government message about keeping your head.
"But the message that there's enough fuel to go around is not quite squaring with what people are seeing on the ground at the moment.
"What we're going to have to see soon is contingency plans in place to make sure we can address any welfare issues and crucially we can keep the food supply chain going as well."
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