New Zealand and France will jointly convene the Christchurch Call leaders' summit, that aims to "take stock of progress and develop a new shared priority work plan".
Prime Minister Jacinda Ardern and French President Emmanuel Macron will co-chair the leaders' meeting on May 15 - the second anniversary of the Call.
The summit will bring together leaders across Call-supporting governments, tech companies and civil society.
The Christchurch Call to Action aims to eliminate terrorist and violent extremist content online.
It came after the 2019 terror attack on two mosques in the city where 51 people were murdered and 40 wounded.
The call is a voluntary framework whereby global governments and tech companies pledge to work towards stopping violent content from being posted online, and preventing such content from spreading so rapidly.
Yesterday it was confirmed the US would formally join the Call, after holding off initially.
This morning it was announced Ardern and Macron would lead the upcoming summit.
"We expect the Call community to refine its focus, redouble its efforts, and agree to a priority work plan for the year ahead," Ardern said.
"Among the priorities I would like to see progressed is a strengthened collective ability to manage crises related to terrorist and violent extremist content online.
"I would like to see us grow our shared understanding of algorithmic processes that have the potential to cause harm, or to radicalise or incite to acts of terrorism and violent extremism. And to develop positive interventions to address these."
Ardern said the inaugural Christchurch Call Community Consultation report would provide the foundation for the work.
Macron said increased transparency on methods used to moderate harmful online content - from companies and governments - would underpin the community's "commitment to uphold fundamental internet freedoms".
"A strengthened Call community is critical to our enduring success," he said.
"It needs to support and empower its members to engage in direct, constructive dialogue on issues of substance, support each other to do better and, where necessary, hold each other to account on delivery of the Call."
Both leaders welcomed the United States' decision to formally join the Christchurch Call.
And they "warmly welcomed" the global super power's intention to attend the virtual leaders' summit.
Both leaders said the support of the US to the Call would "send a powerful message to those who would seek to exploit the internet to promote terrorism and violent extremism".
"The US Government's support recognises the importance of a multi-stakeholder approach to an issue that increasingly transcends borders, ideologies and nationalities, and the ability of any one group or country to address on their own," Ardern said.
"It also recognises the importance of protecting human rights and fundamental freedoms online.
"The major US tech companies are supporters of the Call, and having the US Government on board will further strengthen actions to reduce the risk of the internet being used as a tool for terrorists."
Ardern said the many attacks since the Christchurch massacre, including some in the US, "bear witness to the challenges we face".
"The pervasive threat of terrorist and hateful content online continues to contribute and fuel violent extremism and terrorist actions," she said.
Macron added: "We believe the Call remains a cornerstone of our collective efforts against the presence online of such content."
"It is a global issue that requires a collaborative response by governments, tech companies and civil society, all supporting a free, open and secure internet."
The French President said the work of the Call was ongoing.
"And it remains as important as when it was launched two years ago," he said.
Ardern vowed the Call community would not "waver from our shared belief there is no place online for terrorist and violent extremist content".
The summit will take place on May 15 and is a virtual platform, where the leaders of Call-supporting governments, tech companies and civil society network members will convene to agree a shared work programme for the year ahead.
In the second half of 2019, the governments of New Zealand and France carried out a survey of the Call community, to take stock of the many ways in which supporters are fulfilling their commitments to the Christchurch Call.
From that survey, the Christchurch Call Community Consultation Report was produced.
The report has provided a foundation for work to develop a shared work plan to be agreed at the summit.