Google is updating its free mapping service this week with colour-coding that maps out areas infected with Covid-19 cases, the search giant said in a blog post.

Tapping the new "Covid-19" option in a layer feature in a top corner of a screen will enhance maps using the latest 7-day average of cases per 100,000 people in areas being viewed, it said.

A label will also let users know whether the number of Covid-19 cases in a particular spot is trending up or down, according to Maps product manager Sujoy Banerjee.

The tool is meant to provide "critical information about Covid-19 cases in an area so you can make more informed decisions about where to go and what to do," Banerjee said.

Data used in the COVID layer comes from sources including Baltimore-based Johns Hopkins hospital, the New York Times, and Wikipedia, which get information from public health organizations such as the World Health Organization and government health ministries, according to Banerjee.

The COVID layer is rolling out this week worldwide in versions of the map app tailored for mobile devices powered by Apple or Google-backed Android software, the California based company said.

Google Maps already featured pandemic-related tools such as letting users know when public transit was likely to be crowded.

"While getting around is more complicated these days, our hope is that these Google Maps features will help you get where you need to be as safely and efficiently as possible," Banerjee said.