Tempers are flaring in the southern English port town of Dover where truck drivers say they are trapped, needing a negative coronavirus test to leave the UK but unable to get one.

It follows France relaxing a two-day blockade which has stranded thousands of freight vehicles in the United Kingdom.

The blockade, imposed by France due to a new coronavirus strain being found in the UK, ended after 48 hours of frenzied negotiations among French, British and European Union authorities.

French authorities agreed to allow delivery drivers to enter by ferry or tunnel provided they showed proof of a negative test taken less than 72 hours before their journey.

But thousands of drivers, many from across Europe, have been stuck for days in southern England and many are set to miss Christmas with their families.

With anger boiling over, some have scuffled with police.

On the ground at the port of Dover, there were few signs of tests or support for stranded drivers.

"They talk about some COVID test but there are no COVID tests," Blazej Pankiewicz, a trucker from Torun, Poland, said while surrounded by angry drivers.

Mr Pankiewicz said he was extremely sad to be missing Christmas at home with his family members who had already gathered together.

Truck drivers sounded their horns in protest around Dover.

Many have been eating through their last provisions on the side of the road while their families have gathered for festivities thousands of kilometres away.

"They asked for a PCR COVID-19 test and we don't have anywhere to do that," Stella Vradzheva, a van driver from Strelcha in Bulgaria, said.

"The roads are closed, so if we go we can't come back we are stuck here."

Ms Vradzheva said she and others in her van had been waiting for three days and had only been given some bottled water and a packet of chips.

Britain has said it will hand out tests to some of the 8,000 to 10,000 truckers stranded in the area but it will take time.

A testing unit was supposed to be on its way to the port, according to local officials.

Blockade comes amid looming Brexit deadline

European nations began shutting their borders to Britain on Sunday local time, one day after UK Prime Minister Boris Johnson imposed new lockdown restrictions due to the surge of new infections related to the new COVID-19 strain in London and southern England.

France argued the blockade was necessary while figuring out safety measures to protect European citizens.

On the English side of the Channel, soldiers were being deployed for the mass-testing program to ease the backlog of trucks.

The French travel restrictions had worried many as the UK relies heavily on its cross-channel links to Europe for food, especially for fruit and fresh produce.