Prime Minister Jacinda Ardern has given a glimpse of what she will be discussing with other world leaders in Paris this week.
Ardern and French President Emmanual Macron are hosting a summit aimed at coming up with international agreement on ways to prevent the spread of terrorist and hateful material online.
It comes two months after an alleged white supremacist opened fire in two mosques in Christchurch, killing 51 people.
In an op-ed for the New York Times published on Sunday (NZ time), Ardern said she too inadvertently saw the killer's Facebook livestream.
"Many people report seeing it autoplay on their social media feeds and not realizing what it was - after all, how could something so heinous be so available? I use and manage my social media just like anyone else. I know the reach of this video was vast, because I too inadvertently saw it."
She says 8000 people phoned mental health support lines in the following week, saying they'd seen it.
"Social media connects people. And so we must ensure that in our attempts to prevent harm that we do not compromise the integral pillar of society that is freedom of expression.
"But that right does not include the freedom to broadcast mass murder."
She said at the summit, New Zealand will "present a call to action in the name of Christchurch, asking both nations and private corporations to make changes to prevent the posting of terrorist content online, to ensure its efficient and fast removal and to prevent the use of live-streaming as a tool for broadcasting terrorist attacks".
"It will be a voluntary framework that commits signatories to counter the drivers of terrorism and put in place specific measures to prevent the uploading of terrorist content."
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She said unlike banning the types of weapons used in the attack, New Zealand can't on its own stop Facebook and other platforms being used to spread hate.
Massey University sociology professor Paul Spoonley agrees.
"We have NetSafe, who do their best, but we can't do it by ourselves. International cooperation is essential," he told Newshub.