DOVER, United Kingdom (AFP) - Far-right demonstrators burnt the EU flag on Saturday at a rally in Dover, Britain's closest town to continental Europe.

Police officers in high-visibility jackets surrounded the small number of demonstrators as they marched along the seafront of the southeast English port town.

One man held up an England flag with "Refugees NOT welcome" written on it.

Immigration has been one of the major issues in run-up to the June 23 referendum, when Britain votes on whether to stay in the European Union or leave.

"Far-right demonstrators have not succeeded in their attempts to close the port of Dover," said Charlie Elphicke, the MP for the town.

"Just 30-odd of the far right have turned up. So much disruption created by so few selfish people."

A rival counter-demonstration also took place.

One woman held up a sign that read "Racism hurts everyone".

Dover is 34km away from the northeast coast of France, which is visible across the Channel.

With less than four weeks to go until the referendum, the Remain campaign is on 53 per cent support and the Leave camp on 47 per cent, according to the What UK Thinks website's average of the last six polls.