The EU retains the right to use export controls as a means to "leverage" vaccine firms to fulfil their Covid-19 supply contracts, the Taoiseach has said.
Some countries have complained that doses have not been distributed fairly. As the leader of a coalition of six countries, he demanded a correction mechanism, raising tensions between capitals from where the leaders were holding their remote summit.
Mr Kurz warned: "When member states have a lot less vaccines available to them than others, then I think this is a big issue for Europe".
Addressing a Brussels press conference following a meeting of the European Council on Thursday, Ms von der Leyen said she had "no knowledge" of the United Kingdom exporting jabs, while 77 million doses had been exported by the EU so far.
Under the joint procurement program set up by the European Commission, doses are allocated on a pro rata basis, but some nations are taking less than their share.
The EU is at the start of a third wave of Covid-19 infections but vaccinations are progressing steadily and the bloc is on course to have 70% of adults inoculated in the second quarter, the European Commission's president Ursula von Leyen said on Thursday. AstraZeneca shots are cheaper and easier to handle than vaccines from Pfizer-BioNTech or Moderna.
"It's the end of naivety", Macron told reporters after a virtual European Union summit.
"There are 13 million doses of vaccine waiting for quality control release to be dispatched to COVAX as part of the Company's commitment to supply millions of doses to low-income countries".
Another sensitive issue is the distribution of vaccines which Europe has already received.
That has contributed to a stuttering start to vaccination roll-outs.
AstraZeneca can not export any more COVID-19 vaccines from Europe until is makes good on its contracts with the European Union, EU Commission chief Ursula von der Leyen said after a meeting of the leaders of the 27-nation bloc.
"We can see clearly that British facilities are producing for Great Britain".
She said deliveries of Astrazeneca vaccines will be much lower than contracted, but still with shots from other vaccine manufacturers the European Union is set to hits its 70% adult goal in the summer.
Some leaders stressed that an embargo should be a last resort if negotiations for a better way of sharing vaccine production come up short, but von der Leyen and France'sPresident Emmanuel Macron adopted an uncompromising tone. Even if the move is detrimental to non-EU nations, the European Commission's goal is to force vaccine manufacturers, especially AstraZeneca, to deliver the doses they agreed to in their contracts.
"Together we will ensure that Europeans get their fair share of vaccines", Von der Leyen tweeted.
The commission's proposal has been divisive.
"The EU has an excellent portfolio of different vaccines and we have secured more than enough doses for the entire population".
Ursula von der Leyen told a news conference after a summit of European Union leaders that mortality increases are slower than the spread of the virus, early evidence that having vaccinated most people over the age of 80 is having an impact.
Von der Leyen, seeking to counter accusations that the EU's threat of export blocks amounted to "vaccine nationalism", presented slides showing that 77 million vaccine doses had been shipped from European Union plants to over 40 countries since the start of December.