The National Police Chiefs Council (NPCC) has confirmed officers are being told not to install the NHS Covid-19 app on their work smartphones.
The app detects when users have been in proximity to someone with the virus.
Some officers have also been told they may not need to obey self-isolate alerts generated by the app when downloaded to their personal phones.
Lancashire Constabulary has told staff to call the force’s own Covid-19 helpline instead.
The BBC contacted the North-West of England force after a source revealed the advice.
The source also said officers had been told not to carry their personal phones while on duty if they had activated the app.
Lancashire Constabulary said this was a policy common to all forces and referred further questions to the NPCC.
The NPCC said it was carrying out an urgent review of the policy. This could happen as soon as Tuesday.
NHS Covid-19 launched last Thursday, since when it has been downloaded more than 12 million times.
In addition to contact-tracing, it also offers a way for users to scan codes when they enter a building to log they were there, as well as a means to check if they have symptoms of the coronavirus and to order a test.
But since the app is designed to keep people’s identities secret, this should not be a problem in this case.