The Chief Constable of Greater Manchester has called for coronavirus testing kits to be made available to police officers as a matter of urgency.
The government is working on supplying tests for the police.
More than 1,300 workers are currently absent from Greater Manchester Police because of the virus.
Ian Hopkins says no-one knows how many of those officers actually have Covid-19.
Mr Hopkins told ITV Granada Reports that he is concerned officers without symptoms could be unknowingly spreading it in the community.
At the weekend, the police chief asked retired colleagues to return to work to help them cope with the reduced resources as a result of coronavirus.