It is “perfectly possible” that a far-right attack like that seen in New Zealand could happen in the UK, security minister Ben Wallace says.
He told the Commons the UK was seeing a “growing threat” from the far right.
He added the attack must be a “wake up call” for social media firms, who should be “ashamed” they enabled the shootings to be live-streamed and shared.
The attack on two mosques in Christchurch killed 50 people.
It was live-streamed on Facebook by the gunman, with the footage lasting for 17 minutes.
Despite the original video being taken down, it was quickly replicated and shared widely on other platforms, including You Tube and Twitter.
“We’ve been clear that tech companies need to act more quickly to remove terrorist content and ultimately prevent new content being made available to users in the first place,” Mr Wallace said.
He said the government would set out clear expectations of how tech companies should keep users safe and what should happen if they failed to do so in a White Paper on “online harms”, due to be published “imminently”.
Home Secretary Sajid Javid has also called for social media companies to “clean up their platforms” or be prepared to face the “force of the law”.
Social media firms sent messages of sympathy to the victims of the attack and said they acted quickly to remove inappropriate content.
Facebook said it had deleted more than 1.5m copies of the video of the attack, of which more than 1.2m were blocked while they were being uploaded.
Youtube said it had also removed tens of thousands of videos and terminated hundreds of accounts created to promote or glorify the gunman.
Mr Wallace acknowledged that the UK’s stricter gun laws made it harder for people to acquire military-style weapons.
However, he said the UK still faced a “growing threat” from the extreme right, which he described as “the pool that terrorists of the future will recruit from.”
He said the government’s counter-terrorism strategy was designed to address all forms of terrorism, whatever ideology it was driven by, and funding would be kept under review and directed “wherever the threat emerges”.