Singapore is distributing a digital contact-tracing device to people who don't use smartphones, as part of the city-state's efforts to contain coronavirus.

The TraceTogether Tokens are aimed at vulnerable seniors who aren't digitally connected but are at higher risk from coronavirus, according to a statement from the Smart Nation and Digital Government Office (SNDGO).

Distribution started on Sunday and the tokens aim to protect people without smartphones in the same way as the existing TraceTogether app, which uses Bluetooth to alert users if they have been in contact with someone who has tested positive for coronavirus.

The tokens send Bluetooth signals to other tokens, or smartphones with the app, and each one uses a personalized QR code.

Coronavirus tracking has sparked concerns about privacy around the world, but the SNDGO says any data recorded will be encrypted and stored for only 25 days.

The tokens only collect proximity data, rather than geolocation data, and have no cellular or internet connectivity. This means encrypted data cannot be taken from the token remotely, and the data will only be downloaded if the individual tests positive for coronavirus, according to the statement.

The tokens have an estimated battery life of six to nine months and don't need to be charged, plus they're small and light enough to hang from a lanyard.

Teams of volunteers will deliver the tokens and provide simple instructions for use, said SNDGO, which is continuing to develop their design and functionality for future batches.

Singapore was one of the first countries to roll out a fully functioning Bluetooth tracking app. The app asks for some personal information, like a mobile phone number, and data is shared with health authorities after a positive coronavirus diagnosis.

The app is voluntary and by June 8 it had been downloaded by 1.8 million people, according to a government fact sheet. In June last year, Singapore recorded a total population of 5.7 million.