A health worker holds up a vial of Covishield, AstraZeneca-Oxford's Covid-19 coronavirus vaccine, as they administer a dose at the Ayeyarwady Covid Center in Yangon on Jan 27, 2021. (YE AUNG THU / AFP)

The European Union said it may limit exports of COVID-19 vaccines after manufacturer AstraZeneca said production difficulties meant it would not be able to supply the expected amount of doses to the bloc.

The EU signed a deal with Astra-Zeneca in August for 300 million doses, with an option for a further 100 million

Another supplier, Pfizer-BioNTech, also said it will deliver less than expected, dealing a blow to the 27-member bloc's central vaccine procurement program.

"Europe invested billions to help develop the world's first COVID-19 vaccines," said European Commission President Ursula von der Leyen in a live video address at the virtual World Economic Forum. "And now, the companies must deliver. They must honor their obligations."

"This is not about EU first, this is about Europe's fair share," added Germany's Health Minister, Jens Spahn.

EU Health Commissioner Stella Kyriakides said the bloc would "take any action required to protect its citizens" and that any exports of vaccine produced in the EU to countries outside it would require early notification.

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Another meeting with suppliers was expected to take place on late Wednesday, she said, adding the EU wanted to see "a detailed planning of vaccine deliveries."

The United Kingdom, which completed its exit from the bloc at the turn of the year, has made swift progress with its own vaccination program, but may still suffer the aftershock of the EU's problems as one of its sources is a Pfizer factory in Belgium.

The UK's Minister for COVID Vaccine Deployment, Nadhim Zahawi, admitted supplies are "tight" but added: "I'm confident that (AstraZeneca and Pfizer-BioNTech) will both deliver for us the quantities that we need to meet our mid-February target and of course beyond."

AstraZeneca said it was "doing everything it can to bring its vaccine to millions of Europeans as soon as possible".

The EU signed a deal with Astra-Zeneca in August for 300 million doses, with an option for a further 100 million, which Sky News reported was for an upfront fee of 298 million pounds (US$407 million). It had hoped that 80 million of those doses would be available for use by March.