Prime Minister Jacinda Ardern says although Facebook's moves to crack down on white nationalism were positive, it's something the social media giant should have already been focusing on.

Speaking to media in Christchurch today, Ardern said there was "still more work to do" and called for a global, co-ordinated response to hate speech in social media around the world.

Last night (NZ time) Facebook announced its intention to crack down on white nationalism on its social media sites.

"Today, we're announcing a ban on praise, support and representation of white nationalism and separatism on Facebook and Instagram, which we'll start enforcing next week," the statement said.


"It's clear that these concepts are deeply linked to organised hate groups and have no place on our services," the statement said.

This comes after the March 15 terror attack on two mosques in Christchurch, where the alleged gunman killed 50 people and live-streamed much of the rampage on Facebook Live.

But Ardern said Facebook's announcement should have always fallen within Facebook's guidelines of hate speech.

"But, nevertheless it's positive the clarification has now been made in the wake of the attack in Christchurch."

She noted that the Australian Government was looking to introduce legislation which would impose penalties on social media companies if they did not restrain the spread of "extremist material".

Ireland and Germany were also looking to put in place measures to address harmful content, Ardern said.

She added that this reflected the "broader international community's view that more needs to be done to resolve the problem we face while preserving a free, open and secure internet".

New Zealand, Ardern said, has a role to play in this debate and in "much-needed reform".

She said she would be working collaboratively to find meaningful solutions – "ultimately, we can all promote good rules locally".


But platforms, such as Facebook, Youtube and Twitter were all global.

"Therefore," Ardern said, "the solutions will need to be [global] too".

Meanwhile, Twitter's head of legal, policy and trust Vijaya Gadde said the social media firm had removed 20,000 Tweets since the attacks, but admitted it "feels like a leaky bucket".

She gave Twitter an "A for effort" in dealing with how it responded, in the aftermath of the terror attack.