The company said the staff had been asked to stay at home as a precautionary measure and it was examining whether the measures would impact production at the site.

Health officials were still investigating what caused the outbreak, a spokesman of the Hamburg health authority said.

It was also still unclear whether the workers had caught the more contagious variant of the coronavirus which was first discovered in Britain and is now rapidly spreading across Europe, he added.

Health authorities first ordered the quarantine on Friday and would probably be able to give more details on the virus type in the second half of next week, the official said.

Airbus employs more than 12,000 people at its Hamburg-Finkenwerder site, making it the northern city's largest industrial employer.

"The cause of the cases is still under investigation. We are fully supporting the authorities," an Airbus spokesman said.

On Saturday, health authorities put Berlin's Humboldt hospital under quarantine after 20 patients and staff tested positive for the more infectious variant.

The quarantine covered about 1,500 doctors, nurses and technicians working at the hospital as well as more than 400 patients.

(Reporting by Michael Nienaber, Editing by Andrew Heavens)