The summit comes as there is a growing realisation that the current abuse of social media by extremists must be countered, after the Christchurch attacker broadcast live footage on Facebook from a head-mounted camera.
A "one-strike" policy at Facebook Live will be applied to a broader range of offenses, with those who violate serious policies suspended from using the feature after a single offense.
Facebook said Tuesday it would ban users from its Live streaming feature for a set period of time if they violate certain community guidelines.
"For example, someone who shares a link to a statement from a terrorist group with no context will now be immediately blocked from using Live for a set period of time".
"We plan on extending these restrictions to other areas over the coming weeks, beginning with preventing those same people from creating ads on Facebook", Rosen said.
Facebook has come under intense criticism for its handling of the gunman's video on its platform.
To assist with such purges, the company is investing $7.5 million in research, across the University of Maryland, Cornell University and the University of California, Berkley, to improve video detection software.
Ms Ardern said co-operation on ending extremist content online was the least that should be expected from Facebook.
Tristan Harris, co-founders of the Centre for Humane Technology, who formerly worked for Google, warned that online platforms like YouTube, where 70% t of video watching time is via its recommendations, pushed people towards harmful content.
Part of the ongoing effort would look at videos depicting events that never happened, he said.
"We did have permissive gun laws", she said, as weapons used in the 15 March attacks were easily obtained and modified.
This move was portrayed as an effort to tackle hate speech before it could erupt into something more destructive.
"I've spoken to Mark Zuckerberg directly, twice now, and actually we've had good ongoing engagement with Facebook".
Rebel Wilson and Anne Hathaway sat down with TVNZ UScorrespondent Rebecca Wright to discuss their new film "The Hustle" when they shared words about NZ Prime Minister Jacinda Ardern.