Bomb disposal team called to UK vaccine plant
Production was halted and staff were evacuated from the Wockhardt site in Wrexham, north Wales, following the discovery.
The pharmaceutical and biotech company said later that the package was made safe and employees were allowed back into the building.
No further details were given about the nature of the package.
"This temporary suspension of manufacturing has in no way affected our production schedule and we are grateful to the authorities and experts for their swift response and resolution of the incident," a spokeswoman said.
North Wales Police closed roads in and around the site during the operation.
Wockhardt provides the final stage of services in preparing the Covid-19 vaccine developed by the British drugs group AstraZeneca and Oxford University.
Prime Minister Boris Johnson visited the manufacturing facility in north Wales in November, posing for photographs with vials of the AstraZeneca vaccine manufactured there, shortly before it received regulatory approval in the UK.
Last week, emergency teams were called out to protect vaccines supplies following flooding in the area.