The Osaka summit ended on Saturday afternoon with a warning to the social media companies to lift their standards, a message backed by all members including US President Donald Trump after months of Australian diplomatic effort.
Mr Morrison contacted New Zealand Prime Minister Jacinda Ardern soon after the outcome to relay the news given her demand in April that social media companies stop the capacity to “livestream murder” and spread terror.
The statement from the G20 puts pressure on the companies to act immediately when contacted by authorities to remove terrorist content such as the live video of an attack or other violent posts that seek to promote terrorism or recruit followers.
“We all appreciate the great opportunities that these new platforms provide – we want to ensure that they’re realised,” Mr Morrison said in an interview with The Sun Herald and The Sunday Age.
“But at the same time, the chilling reminder from Christchurch was that we’ve got to protect these tools from being weaponised by terrorists. That is important to ensure we realise their positive benefits so people don’t lose confidence in these platforms because of the failure to keep them safe.”
The G20 statement was proposed by Australia and agreed by consensus after support from Japanese Prime Minister Shinzo Abe as host of the meeting, as well as French President Emmanuel Macron, Canadian Prime Minister Justin Trudeau and German Chancellor Angela Merkel and the European Union leaders.
“It was pursued country to country, partner to partner, it was about fostering cooperation and there was no grandstanding about this,” Mr Morrison said.
“Shinzo Abe was incredibly important. Without him providing the opportunity, obviously it would not have been possible.”
While the G20 statement cannot bind the companies, given any laws or rules are up to each nation, it tells the social media and internet sectors to expect direct intervention by governments if they do not fix the problem.
Mr Morrison wrote to Mr Abe in the days after the Christchurch terror attack in March when an Australian gunman killed 51 people and wounded 49 while streaming the murders on Facebook.
The letter set out a proposal for a global agreement to stamp out terrorist violence on social media but the idea faced initial resistance from the US and others because of concerns it could curb free speech.
Mr Morrison overcame those concerns and the result was the consensus agreement reached at this week’s meeting.
The joint statement was a significant breakthrough because Mr Trump and his officials had expressed concern about any stance that could be seen as a restriction on freedom of speech.
The G20 leaders said they issued their statement to “raise the bar” for online platforms.
“The internet must not be a safe haven for terrorists to recruit, incite or prepare terrorist acts,” they said.
“Platforms have an important responsibility to protect their users.”
Tough Australian laws already require social media companies to act upon instructions from police and other authorities to remove violent terrorist material under legislation put forward by Mr Morrison and backed by Labor in Parliament in early April.
The government set up a taskforce to act on the laws with members including Google, Facebook, Twitter, Amazon and Microsoft as well as the communications companies that carry most internet traffic, Telstra, Optus, Vodafone and TPG.
All are subject to amendments to the Criminal Code that imposes fines worth billions of dollars if they do not act on police warnings about “abhorrent violent material” they host.
The taskforce report, to be released on Sunday, includes pledges from the social media companies to control live streaming, monitor new accounts, remove users who breach standards and do more to moderate content.
It also recommends a the government run a “terrorist scenario” at some time in the next 12 months to test the response of social media networks.
A new reporting regime will require the companies to tell the government twice each year about their efforts in stopping terrorist content.
David Crowe is chief political correspondent for the Sydney Morning Herald and The Age.