Google will publish location data from its users around the world from Friday to allow governments to gauge the effectiveness of social distancing measures put in place to combat the COVID-19 pandemic, the tech giant said.

The reports on users' movements in 131 countries will be made available on a special website and will "chart movement trends over time by geography," according to a post on one of the company's blogs.

Trends will be display "a percentage point increase or decrease in visits" to locations like parks, shops, homes and places of work, not "the absolute number of visits," said the post, signed by Jen Fitzpatrick, who leads Google Maps, and the company's chief health officer Karen DeSalvo.

"We hope these reports will help support decisions about how to manage the COVID-19 pandemic," they said.

"This information could help officials understand changes in essential trips that can shape recommendations on business hours or inform delivery service offerings."

Like the detection of traffic jams or the measurement of traffic on Google Maps, the new reports will use "aggregated, anonymised" data from users who have activated their location history.

No "personally identifiable information," such as a person's location, contacts or movements, will be made available, the post said.

The reports will also employ a statistical technique that adds "artificial noise" to raw data, making it harder for users to be identified.

From China to Singapore to Israel, governments have ordered electronic monitoring of their citizens' movements in an effort to limit the spread of the virus, which has infected more than a million people and killed over 50,000 worldwide.

In Europe and the United States, technology firms have begun sharing "anonymised" smartphone data to better track the outbreak.

Even privacy-loving Germany is considering using a smartphone app to help manage the spread of the disease.

But activists say authoritarian regimes are using the coronavirus as a pretext to suppress independent speech and increase surveillance.

And in liberal democracies, others fear widespread data harvesting and intrusion could bring lasting harm to privacy and digital rights.