The government has put the army on standby and soldiers will be deployed if needed amid the ongoing fuel supply crisis.
It comes as panic-buying continues, with consumers apparently ignoring pleas to stop.
Queues at service stations around the country continued on Monday and many ran out of fuel.
Army tanker drivers will now receive specialised training ahead of any possible deployment.
Business Secretary Kwasi Kwarteng said: “While the fuel industry expects demand will return to its normal levels in the coming days, it’s right that we take this sensible, precautionary step.
“The UK continues to have strong supplies of fuel, however we are aware of supply chain issues at fuel station forecourts and are taking steps to ease these as a matter of priority.
“If required, the deployment of military personnel will provide the supply chain with additional capacity as a temporary measure to help ease pressures caused by spikes in localised demand for fuel.”
Meanwhile, Transport Secretary Grant Shapps has authorised an extension to ADR driver licences, which allow drivers to transport goods, such as fuel.
This will apply to licences expiring between 27 September and 31 December, and extend their validity until 31 January 2022.
“Extending ADR licences will further help ease any pressures on fuel drivers by removing the need for refresher training courses and ensuring they can keep providing their vital service on our roads,” Mr Shapps said.
Petrol retailers had been hoping for a return to normal after motorists drained pumps over the weekend.
But there was little sign of the panic-buying diminishing on Monday.
Earlier a joint statement from BP, Shell UK, Esso Petroleum/ExxonMobil, Wincanton, Certas Energy UK, Hoyer Petrolog UK, Greenergy, Fuels Transport & Logistics, Downstream Fuel and Suckling Transport urged drivers to buy fuel as they normally would.
They said: “There is plenty of fuel at UK refineries and terminals, and as an industry we are working closely with the government to help ensure fuel is available to be delivered to stations across the country.
“As many cars are now holding more fuel than usual, we expect that demand will return to its normal levels in the coming days, easing pressures on fuel station forecourts. We would encourage everyone to buy fuel as they usually would.
“We remain enormously grateful to all forecourt staff and HGV drivers for working tirelessly to maintain supplies during this time.”
The panic buying has led to industries from taxi drivers to the meat processing sector – and even non-league football – facing difficulties and prompted calls for healthcare workers to be given priority access to fuel.
The British Medical Association said there was a real risk that some would not be able to get to work.
And Unison called on ministers to use emergency powers to “designate fuel stations for the sole use of key workers” – and call backed by the Royal College of Nursing.
“The Government has to take control. It’s no good ministers wasting time on a pointless blame game or pretending there’s no problem,” Unison’s general secretary Christina McAnea.
“Essential staff must be able to get to their jobs so they can continue to provide the services so many rely upon.”
But the Petrol Retailers’ Association (PRA), representing two-thirds of all UK forecourts, said that with many drivers’ tanks now full after the weekend it was watching for an “easing of demand”.
The crisis mushroomed after the disclosure last week that a few petrol stations had seen supply disrupted, due to the nationwide shortage of HGV drivers, prompting widespread panic-buying.
It was still in evidence for a fourth day on Monday, with roads gridlocked as motorists queued for more than an hour in some cases, with lines of cars trailing out of forecourts onto the public highway.
Some petrol retailers – Asda and EG group – have been restricting fuel sales to £30 a time.
Even if the buying frenzy does abate, motorists face a further headache as the price of Brent crude on international oil markets continued to climb, reaching a three-year high of just under $80 a barrel – likely to result in higher prices at the pumps to come.