Britain's health minister Jeremy Hunt threatened to impose new regulations on social media firms unless they do more to protect young people using their services.
Hunt said the groups were "turning a blind eye" to the effect social media had on children's well-being - an accusation that comes as Facebook and others face heightened scrutiny worldwide over their impact and influence.
Hunt did not say what kind of regulations the government could impose, but gave the companies an end-of-April deadline to come up with measures to tackle cyberbullying and control the amount of time youngsters spent online.
"I am concerned that your companies seem content with a situation where thousands of users breach your own terms and conditions on the minimum user age," Hunt said in a letter sent to tech firms.
"I fear that you are collectively turning a blind eye to a whole generation of children being exposed to the harmful emotional side effects of social media prematurely."
In an article in the Sunday Times newspaper, Hunt said there had been a few welcome moves to improve children's online protection, but that the overall response had been "extremely limited" and that a voluntary approach might not be enough.
"An industry that boasts some of the brightest minds and biggest budgets should have been able to rise to the challenge," he added.
Hunt's comments came alongside the announcement of a government review of the impact that sites like Facebook, Twitter and Snapchat have on children's mental health.
Britain has clashed with internet companies on several fronts in recent years overpayment of taxes, action against the spread of fake news and extremist material, and their use of personal data.
"We welcome the Health Secretary's continued engagement on this important issue and we share his ambition to create a safe and supportive environment for young people online," said Karim Palant, Facebook UK Public Policy Manager.
Google UK's Public Policy Manager, Katie O'Donovan, said the company had introduced features to help parents set screen time limits and launched an online safety course for children.
"Along with all parents, we understand the challenge of helping children make the most of the internet in a safe and responsible way," she added.
© Thomson Reuters 2018