Italy has blocked a shipment of AstraZeneca's coronavirus vaccine bound for Australia.

This is the first time that vaccine exports have been prevented under new EU rules introduced in January.

The Italian government announced on Thursday that it had stopped the export after AstraZeneca had requested permission to send about 250,000 doses from a plant in the country.

The new EU scheme requires pharmaceutical companies to obtain authorization for exports out of the bloc from the member state where the vaccine is produced.

The Italian government says the decision was made due to a persistent shortage of vaccines and delays in delivery in Italy and the EU.

It also cites the higher number of doses for Australia compared with the amount supplied to Italy and the EU.