Italy became the first country to impose an EU export ban on coronavirus vaccines on Thursday after blocking a shipment of 250,000 AstraZeneca jabs to Australia.
Brussels introduced the export transparency regime during its row over supply shortfalls with the British-Swedish pharmaceutical company at the end of January.
Under the new rules, manufacturers in the EU must ask national authorities in the country of production and the European Commission for permission to export vaccines outside the EU.
EU allies including Britain, have raised concerns about the regime, which was a response to fears that vaccines bought by Brussels were being shipped elsewhere.
Italy blocked the export of the vaccines and the commission did not raise any objections, the Financial Times reported. Rome notified Brussels of its decision at the end of last week.
Mario Draghi, the Italian Prime Minister who took office in February, called for stricter export controls at an EU summit last month. He urged EU leaders to speed up vaccinations in the bloc in his first meeting of the bloc's heads of state and government.
AstraZeneca in January cut its supplies to the EU in the first quarter to 40 million doses from 90 million foreseen in the contract, and later said it would cut deliveries by another 50 per cent in the second quarter.
New Zealand has ordered 7.6 million doses of the AstraZeneca vaccine and had anticipated receiving nearly 250,000 doses before July as part of its deal with international alliance Covax.
The EU is lagging far behind countries such as the US, Britain and Israel in its vaccination roll-out and Brussels has blamed the supply shortfalls.
The company says it did not break its contract with the EU, which negotiated for the jabs as a bloc but refused to comment on the ban.
An EU official confirmed the commission had approved the ban. Reuters reported another EU source as saying the commission backed the ban because of AstraZeneca's failure to meet contractual obligations on supplies.
Italy has 1.5m AstraZeneca vaccines and administered 322,800 doses. In total, it has given out 4.3m vaccines from all companies. The EU has administered out 8.02 doses per 100 people, while the UK has given out 32.34 doses.
An EU diplomat accused AstraZeneca, which has vowed to increase its supplies, of not acting in "good faith" with the bloc.
The diplomat said, "Italy has sent a crystal clear message to AstraZeneca. Contracts are to be honoured."
The diplomat said that vaccine deliveries to the EU were "putting 30 million European lives at risk".
"Being in this situation, not making up for it, not even offering excuses to the people they have let down and then asking for an export authorisation is a very brazen move. Italy rightly stopped it," the diplomat said.
Another EU diplomat suggested that member states were split over the Italian course of action.
The diplomat said, "There is a difference between Member states on the nature of the export regime: is it purely a monitoring mechanism or does it enable a state to block exports? Draghi has clearly chosen the latter."
AstraZeneca had requested permission to export the 250,000 doses from its Anagni plant, near Rome. The plant is handing the final stage of production - the so-called fill and finishing of its Covid-19 vaccine.
The site is owned by US group Catalent that was expected to handle hundreds of millions of AstraZeneca doses over the coming 12 months.
Britain feared it would be the first victim of the EU vaccine ban at the height of the commission's row with AstraZeneca in January. There were suspicions in Brussels that EU AstraZeneca jabs had been shipped to the UK.
The commission drew fierce criticism at the height of its row with AstraZeneca when it threatened to trigger Article 16 of the Northern Ireland protocol, which would impose a hard border on the island of Ireland.
The move was designed to prevent vaccines being smuggled into the UK from Northern Ireland if an export ban was imposed on Britain, which had ordered millions of Pfizer jabs from EU plants.