Prime Minister Jacinda Ardern has opened the Christchurch Call summit in Paris with an appeal to tech companies to review their business models that can pull users down dark rabbit holes to radicalisation.
And she is asking online platforms like Facebook, YouTube, and Twitter – considered to be so global in reach to not have to answer to anyone - to be more transparent by publishing progress reports regularly.
Ardern arrived at the Elysee Palace to a French guard of honour and a warm la bise greeting - a kiss on each cheek - from French President Emmanuel Macron, who hosted lunch.
Later representatives from Facebook, Twitter, Google, Microsoft, Wikimedia and Qwant as well as the leaders of seven countries and the European Union arrived for the summit.
The Christchurch Call to Action aims to take collective action to prevent a repeat of how the terror attack on March 15 was weaponised on social media.
"I stand before you with the 51 lives lost in New Zealand heavy on my mind," Ardern said in her opening address to the summit.
"The hearts of Aotearoa still ache … Let us all here the call from Christchurch today."
Ardern asked tech companies to enforce the standards they already have by preventing such content from being uploaded in the first place.
She also addressed the business models of social media companies that are designed to grab users' attention in a way that can pull them into a single and increasingly radical narrative.
"We ask that you assess how your algorithms funnel people to extremist content and make transparent that work.
"Some of this is already under way. But we need to see the progress you are making. We are asking you to report regularly in a verifiable and measurable way."
The gunman's video from March 15 – which was taken down from Facebook 1.5 million times - had gone viral and was still available today.
"It's hard to quantify the harm this caused. But the fact it caused harm is unquestionable," Ardern said.
"The video persists, despite efforts taken to date to remove it. Those wanting to perpetuate grief or hate keep finding ways to cut and share the video and outwit the efforts of the companies in this room to stop its spread."
The call, due to be signed and released at 4am (NZT), is understood to be a voluntary framework for governments and tech companies to work individually and collaboratively to stop online platforms from hosting terrorist content and violent extremism.
Ardern said it was governments' responsibility to impose a duty of care on online platforms through legislation and regulation, but also to build inclusive societies that reject and resist acts of terrorism and violent extremism.
"Our societies must be compassionate and inclusive no matter what religion, race or gender, and we cannot call for others to model this behaviour unless we model it ourselves."
The opening of the summit featured a Maori karanga by Ngati Ranana that included the sounding of the conch to acknowledge "those who have passed, those of us who remain, and why we are here".
Ardern then closed her speech in Maori: "He aha te mea nui o te ao? What is the most important thing in the world? He tāngata, he tāngata, he tāngata. It is the people, the people, the people."
She said online platforms were a powerful tool with many benefits, but they can also be harmful.
"When they harm, they harm people. And it is people who have the power to determine how they evolve. Let us determine that together."
Earlier in the day she met with tech company representatives in a roundtable meeting.
She also had a 30-minute meeting with Twitter boss Jack Dorsey and bilateral meetings with Norwegian Prime Minister Erna Solberg and Jordan King Abdullah II bin Al-Hussein.