The free SwissCovid application uses Bluetooth wireless technology to register other phones that come within two metres for around 15 minutes or so.
It then alerts people who may unwittingly have been in prolonged proximity with someone who later tested positive for the novel coronavirus.
“We want to stem the uncontrolled spread of the new coronavirus,” the government said Wednesday in a statement.
“The more people use the app, the better we can achieve this goal.”
The app is optional and no personal data or location information is used. Anyone who tests positive for the virus is given a code by the regional health services to enter into the app.
Other app users who spent time in close proximity are anonymously informed, told which day the contact happened on, and are given information on what to do next.
The app was originally road-tested by army conscripts.
Some 1,681 people have died in Switzerland out of nearly 31,300 who have tested positive for the virus in a country of 8.5 million people.
However, infection, hospitalisation and death rates having been low and stable for some weeks.
Switzerland stopped short of imposing strict confinement when it introduced measures in mid-March aimed at stopping the spread of the new coronavirus.
It began gradually easing its restrictions on April 27, with a fourth stage on Monday lifting the maximum limit on gatherings to 1,000.
“Even if the Federal Council continues to ease the measures, the coronavirus crisis is not yet behind us. Sustained efforts are needed to prevent the infection rate from rising again,” the government said.
The government also announced that COVID-19 tests would be free for everyone from Thursday, covering the cost of an infection test which can be as high as 169 Swiss franc ($178, 158 euro).
“The risk was therefore that some people would give up testing if they had to pay for it,” it said.
Will it be compulsory?
No. The app is voluntary.
The government has also promised that the app will be discontinued when the virus can be brought under control by other means.
Some Swiss politicians have argued that the app must be made mandatory.
SVP councillor Andrea Gmür said “for the app to be effective, it needs to be mandatory during the acute emergency phase”.
At this stage however the government has said it will remain voluntary.
Photo: OLIVIER DOULIERY / AFP
How much will it cost?
The app is free for all smartphone users.
Will it be effective?
With contact tracing apps proving effective in several Asian countries, researchers have been looking to implement something similar in Switzerland.
There have however been privacy protection issues, as well as concerns that it will not be effective unless it is downloaded by at least 60 percent of Swiss society.
Researchers from Oxford University have said that the app will be ineffective with a lower percentage signup.