Campaigners and politicians have warned that predicted increases in petrol prices by as much as 8% would cripple Scotland's economy.
The Retail Motor Industry Independent Petrol Retailers Association (RMI Petrol) said rises in VAT and fuel duty were forcing up costs at forecourts.
It said prices could increase by 3% this month and 8% by the start of 2011.
SNP and Liberal Democrat leaders said large parts of Scotland relied on cars, lorries and buses.
Scottish Liberal Democrat leader Tavish Scott MSP urged the UK government to cut fuel taxation.
He said: "Island and rural Scotland depends on the car, lorry and in a couple of weeks, the school bus.
"A surge in petrol prices forced by speculators and rich oil barons across the world is the worst economic news for Scotland."
The SNP Westminster transport spokesman Angus MacNeil said higher costs would hamper the UK and Scotland's economic recovery.
He said: "These increases will have a crippling effect on businesses and households and the Treasury must end this highway robbery.
"It's a national scandal that, in an oil rich country like Scotland, we are paying the highest fuel prices in Europe. The Treasury cannot justify hammering hard pressed motorists and businesses."
Erica MacDonald, of Barra, has been campaigning against high fuel costs on the Western Isles.
She said prices on South Uist were already hitting £1.34 for a litre of petrol and described the prospect of a further price rise as "frightening".
Ms MacDonald has gathered 3,000 names for a petition and 1,500 followers to a Facebook campaign in a protest over costs.
The petition also urges the UK government to include Scotland's rural areas in a proposed pilot project offering petrol and diesel at reduced costs.
According to website PetrolPrices.com, which gathers data from fuel card users, the highest prices in Scotland ranged from £1.16 to £1.29 for a litre of petrol.
For diesel, costs ranged from £1.18 to £1.30-a-litre.
In Aberdeen and Edinburgh, the website records £1.16 as the highest petrol price.
The cost in Dumfries was £1.17, £1.18 in Glasgow and £1.22 in Stirling.
In Inverness the highest price was £1.20 and going up to £1.23 in Thurso, £1.27 in Stornoway on Lewis and £1.29 in Lerwick, Shetland. Prices were not available for Orkney.