The UK Government has warned that a strike by workers at the Grangemouth refinery could cause "disruption" to fuel supplies.
Energy Secretary John Hutton said the first stage of contingency plans to ensure fuel supplies were now active.
Operators Ineos have begun a scaled shutdown of the plant in anticipation of a two-day strike this weekend by Unite union members.
Despite the warning, Mr Hutton urged motorists to buy fuel as normal.
He said: "A strike could cause disruption to people who depend on the Grangemouth refinery for fuel supplies.
"If the strike does go ahead, we will do everything in our power to minimise disruption. We have contingency plans in place and today I have activated the first stage of those plans.
"This allows fuel suppliers to work together effectively to maximise available fuel.
"Everyone can help in this by just buying fuel as normal - buying extra causes problems in the system which would otherwise not exist."
Mr Hutton's comments come as Ineos was accused of "economic terrorism by the Unite union, which is in dispute over changes to members' pensions.
The company has warned that a strike would mean "chaos" for fuel supplies.
However, the union said the company was "scaremongering" over the impact of the strike.
The issue has prompted Scotland's First Minister Alex Salmond to urge the two sides in the dispute to reopen negotiations.
He has also outlined the government's contingency plans if there is a total shutdown at the plant.
Production is expected to be hit as the first of the crude oil units is closed in a phased shutdown of the refinery, one of only nine in the UK.
The plant supplies the whole of Scotland, Northern Ireland and the north of England.
Alex Salmond said both sides in the dispute needed to thrash out a deal prior to the planned action on 27 and 28 April.
If the strike does go ahead, he said the government would be taking measures to secure fuel supplies and he has asked emergency services, local authorities and key agencies to get together and discuss needs at a local level over the next two days.
Forecourt customers react to the potential shortages
Drivers have been urged not to panic buy at the forecourts.
Grangemouth's operators Ineos had earlier accused the Unite union of refusing to attend peace talks at the conciliation service, Acas, in a bid to break the row.
The union said there had been a "tentative" approach by Acas adding: "We have not refused but we have said there has to be something to discuss."
However, national officer Phil McNulty said the company was trying to scare people about the effects of the strike.
He said: "The company appears to be inundating the press with stories about imminent petrol shortages, but the fact is that the refinery is still in full production and there is no industrial action going on.
There's not really much point in having lots of cars with lots of fuel in their tanks going absolutely nowhere when we've got stations without fuel
John Swinney Finance Secretary
"Indeed, there is no need for any shortages if the company simply withdraws its outlandish attempt to grab money back from the pension fund."
Ineos chief executive, Tom Crotty, said: "We have always made it clear that the company is ready to attend talks at Acas to help end the current dispute."
Mr Salmond said the Scottish Government had asked Scotland's eight Strategic Co-ordinating Groups (SCGs) - which comprise the emergency services, local authorities and other key agencies - to consider the issues that may need to be addressed locally in the event of any disruption to fuel supplies.
Speaking on BBC Radio Scotland's Good Morning Scotland programme, Finance Secretary John Swinney said it was essential that both the trade unions and management talked to each other to resolve the dispute.
He added: "There's plenty of evidence that both sides are able to talk, the only thing is they're not talking to each other and that's the way this dispute must be resolved, by these two parties coming together and resolving their differences."
The Government Sub Committee on Civil Contingencies has been meeting since Friday and local authorities and the emergency services are putting contingency plans into place in case of strike action.
Mr Swinney said there were significant reserves available but he urged people not to go out and panic buy.
"There's not really much point in having lots of cars with lots of fuel in their tanks going absolutely nowhere when we've got stations without fuel.
"So, I'd ask people to be responsible.
"We're doing everything we can to encourage a resolution of this dispute and avoid any interruption to the continuity of supplies but the government will take all the steps that we can to make sure the Scottish economy is able to continue to function as effectively as it can," said Mr Swinney.
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