Family Link - created by Google - allows adults to track what their children are doing on their phones and block it at the touch of a button following growing concerns that youngsters are becoming "addicted" to their gadgets.
Saurabh Sharma, head of Family Link, told the Daily Telegraph newspaper: "Children are getting access to devices at younger ages and parents have told us that they know it is important for them to be a member of the digital world.
"But they are also worried that they are spending too much time on devices and running into inappropriate content."
Parents need to set up a Google account on the phone they want to safeguard and download the Family App on their own device. They will then be given weekly or monthly usage reports which show what apps their child is using.
The app is designed for under 13s - although anyone can use it - and parents must approve anything their child/children try to download onto their phones.
However, the app won't work if the children are offline.
Dr Geoff Debelle, child protection officer for the Royal College of Paediatrics and Child Health, said recently: "We live in a digital age with schools using tablets in lessons, classes being delivered online and mobile phones and social media being one of the main ways young people connect and learn - we need to accept that electronic devices are a staple part of daily life.
"However, while the digital world has is benefits, you cannot ignore the dangers it can pose. This new app could be one way parents ensure children are not exposed to too much screen time. It could also protect from the sinister side of digital life such as predatory behaviour and this should be welcomed.
"But there are reservations when it comes to other dangers such as advertising. We would want to ensure that these types of apps provide protection here too."