AstraZeneca's deliveries to the European Union have been beset by delays.
AstraZeneca only delivered half of the doses it was scheduled to ship to European Union member states this week, the company said on Friday.
"We communicated to the European Commission and member states last week that one of the two batches (of vaccine) for delivery this week would need to be tested and would be delivered soon," a spokesperson said.
"AstraZeneca remains on track to meet its delivery plans for the second quarter."
He added that weekly deliveries generally show small fluctuations depending on a number of operational factors such as distribution or the successful completion of safe and quality tests.
A spokesperson for the European Commission told Euronews that they "remain in contact with the company to ensure timely delivery of a sufficient number of doses".
"In this context, we have also launched a dispute resolution with the company on the basis of which we hope to reach an agreement on the outstanding issues," they added.
The Anglo-Swedish pharmaceutical has been harshly criticised by European authorities for delivering about half of the doses it was contracted to in the first three months of the year. It has also already announced that that it would miss its delivery target to the bloc in the second quarter as well.
Brussels has ordered 300 millions doses of the AstraZeneca jab.
It comes just two days after the European medicines regulator (EMA) confirmed a "possible link" between the jab and a rare form of blood clot.
The watchdog reiterated its stance that the benefits of the vaccine continue to outweigh the risks but a number of member states, including Italy, France and Belgium, have limited its use to people over a certain 55.
The EMA had flagged that the reported cases of unusual blood clots were mostly observed in women under the age of 60, although it did not conclude that age and gender were clear risks factor.
In the UK, where more than half of the 38.4 million doses administered to date were from AstraZeneca, its use has been barred for people under the age of 30.