Deliveries to Shell fuel stations are at a standstill after tanker drivers started a strike at 6am today.
The estimated 600 drivers work for Hoyer UK and Suckling Transport, which is contracted to deliveries to Shell's 1000 fuel stations in the UK.
The strike follows the failure of last-minute talks to settle a pay dispute. The drivers want a basic salary of 36,000 a year, a 13% rise on their current wage, but were offered 6.8%.
The strike is scheduled to continue until 6am Tuesday, prompting fears of panic-buying among motorists.
However, the Government has urged calm, pointing out that Shell operates only one in 10 of the UK's fuel stations.
Hoyer's Bernie Holloway said: 'We believe this is a very good offer. Combined with previous pay awards, it produce an overall increase in average earnings totalling 27% over the last four years.
He said the firms would continue to 'explore all possible options to resolve what is clearly a very difficult situation'.
Ron Webb, who represented the drivers through the Unite union, said: 'Our members' dedication helps Shell make vast profits.
'All they are asking for in return is a living wage - one that reflects their skills, their heavy working week and helps make ends meet at a time when every worker in the country is being hit hard by rising fuel and food prices.'
Shell has stressed that the drivers are not employed by it directly, and urged the unions and tanker company bosses to settle their differences.