Executives from the likes of Facebook and Google could reportedly be held liable for harmful content shared on their platforms under U.K. government plans.

Britain is set to unveil legislation on Monday that brings about a new legally-binding duty of care on social media firms to make their platforms safer, The Guardian reported, citing a leaked government document.

A white paper due to be released by the government next week will reportedly include proposals for an independent regulator with the power to dish out fines and hold company executives personally liable for breaches.

Those powers will likely initially come under Britain's media watchdog Ofcom, the newspaper reported, before a new body is established.

The news comes as social media giants face increasing calls to clean up their platforms in the wake of the Christchurch, New Zealand mosque attack. The gunman, who killed 50 people, livestreamed the attack on Facebook, with subsequent copies of the footage being shared on YouTube and Twitter.