Medical experts have been instructed to draw up official guidelines for social media use amid fears over its impact on child mental health, Matt Hancock has revealed.
The health and social care secretary said he was "very worried" as a father by the growing evidence of the detrimental effect on the health of young people.
He told the Observer he had instructed Dame Sally Davies, the UK's chief medical officer, to begin preparing official guidance on safe time limits that would work in a similar way to safe alcohol limits.
Speaking ahead of the start of the Conservative Party conference in Birmingham today, he told the newspaper: "I am, as a father, very worried about the growing evidence of the impact of social media on children's mental health.
"Unrestricted use (of social media) by younger children risks being very damaging to their mental health.
"So I have asked the chief medical officer to bring forward formal guidance on its use by children."
Last year, a report from the Education Policy Institute claimed that more than a third of 15-year-olds can be classed as extreme internet users, with online habits that could have harmful effects on their wellbeing.
Some platforms, including Facebook and Instagram, have moved to mitigate fears of addiction by introducing wellbeing tools that enable users to monitor and restrict their time on the platform.
Public campaigns such as Scroll Free September have also been launched to encourage the public to use social media less.
The initiative from the Royal Society for Public Health (RSPH) asked people to stop using platforms such as Facebook, Instagram, Twitter and Snapchat in September, or to cut down the amount of time they spend on them.
Almost two-thirds of users polled in a July survey considered taking part in the initiative and many believed giving up social media would have a positive impact on their lives, an RSPH survey found.
Mr Hancock hit out at both platforms, which share an owner, over a lack of policing of their rules on age limits.
He told the Observer: "The terms of reference of Facebook and Instagram say you shouldn't be on it if you are under the age of 13. But they do nothing to police that.
"The guidelines for WhatsApp say you shouldn't be on it unless you're 16. But again, they don't lift a finger."