The drive-through facility will now be deep-cleaned and reopened as soon as possible, the outsourcing giant said.
There have been four confirmed cases of Covid-19 among staff within the past 72 hours, first reported by the local newspaper, the Eastern Daily Press.
A G4S spokesperson said: “On Sunday 15 November, a testing site at Postwick, Norwich, was closed after several staff reported positive coronavirus tests.
“The site will be deep cleaned as per Public Health England (PHE) guidelines and reopened as soon as possible. Those with tests booked have been redirected to nearby test sites.”
An outbreak in a healthcare setting is defined as when there is a minimum of two positive cases.
The site is run by G4S, in partnership with the government. There were 43 members of staff working per shift when it was open.
The company said all appropriate safety measures were in place at the site and all PHE, Department of Health and Social Care, and NHS risk assessment management processes were followed.
Members of the public who had booked tests at the site have been told to go to testing centres in Great Yarmouth and in Ipswich, Suffolk.
The Independent has contacted PHE for comment.
Additional reporting by Press Association
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies