Britain's Prime Minister Boris Johnson on Wednesday rejected claims from European Council chief Charles Michel that the country had imposed a ban on Covid vaccine exports.

"Let me be clear, we have not blocked the export of a single Covid-19 vaccine or vaccine components," he told parliament.

"This pandemic has put us all on the same side in the battle for global health. We oppose vaccine nationalism in all its forms."

Johnson's comments came after London summoned an EU diplomat and wrote to Michel to protest about his claim made in a newsletter.

Michel wrote that the UK and US had "imposed an outright ban on the export of vaccines or vaccine components produced on their territory".

Foreign Secretary Dominic Raab called the claims "completely false" and Michel later backtracked.

But Nicole Mannion, deputy head of the EU mission to the UK, was summoned to the foreign ministry for a meeting to "set the record straight" on Wednesday morning.

A European official told AFP on condition of anonymity that a response was being prepared.

The EU maintains that while it exports 30 percent of its vaccines, Britain has failed to publish any data for its own deliveries elsewhere.

The UK insists it is one of the leading donors to the UN's Covax vaccination programme, which has started rolling out in Africa.

The row is the latest in a series of ugly vaccine spats since Britain fully completed its EU departure in January.

More than 22.5 million people have so far received a first jab  in Britain -- one of the highest numbers in the world.

But the EU is under pressure over its own inoculation strategy, and has partly blamed the Anglo-Swedish firm AstraZeneca for failing to fulfil its order because of production issues.

Brussels, Dublin and London were plunged into chaos on January 29 when the EU unveiled plans to unilaterally undo elements of the Brexit deal governing Northern Ireland to stop vaccines from leaving the bloc.

The special post-Brexit trade rules -- painstakingly negotiated since Britain's 2016 decision to split from the bloc to guarantee peace in Northern Ireland -- had been operating for less than one month.

An outcry from Britain, Ireland and Northern Ireland forced the EU into a speedy U-turn -- reversing a plan now widely considered to have been a diplomatic bungle.

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© Agence France-Presse