Police officers in England and Wales are to be told they can download the NHS Covid-19 app on to their personal smartphones and use them at work.
The National Police Chiefs’ Council (NPCC) issued the guidance after carrying out its own technical review of the software.
Individual officers and other police staff will be informed on Wednesday.
The NPCC had previously advised officers not to download the app on any device, while it reviewed its impact.
And they will still be told not to install it on work handsets.
These typically have their Bluetooth functionality disabled.
And the automated contact-tracing process relies on Bluetooth’s wireless signals.
An NPCC spokesman told BBC News some personnel involved in covert and special operations as well as other sensitive roles would also be told to consider not installing the app on any phone until further guidance was issued.
“It is important that we have confidence that the NHS app will work for officers and staff consistently across the country,” he said.
“And it is for this reason that we have recommended that officers and staff download the app to their personal as opposed to their work devices.”
NHS Covid-19 was released to the wider public on Thursday, after several changes to an earlier test version.
It follows the release of similar software in Scotland and Northern Ireland.
The NPCC had been asked to change its policy by the Police Federation of England and Wales (PFEW), which represents about 120,000 officers.
It had appreciated the NPCC wanted to be cautious, it said, but the welfare of its members was “absolutely paramount”.
“It is of course a personal decision if officers now want to download the app.
“However, we would encourage and urge [them] to do so.”
NHS Covid-19 logs when two people’s phones come close to each other.
If one is later confirmed to have the coronavirus, the other can automatically be told to self-isolate for a fortnight.
The app is designed to keep the identities of both parties a secret.
Other functions include a means for users to log visits to restaurants and other leisure venues, via a QR-barcode scan, and then receive a notification if the location is later linked to an outbreak.
Health Secretary Matt Hancock said the app had been downloaded more than 12.4 million times as of 12:00 on Monday.