MELBOURNE: Former New Zealand Prime Minister Jacinda Ardern will take up an unpaid role leading the country's efforts against violent online extremism, the government said on Tuesday.

Ardern stepped down as leader earlier this year, in a surprise decision that brought ally Chris Hipkins to power as head of the centre-left Labour Party.

She will serve as special envoy for the Christchurch Call, a global initiate she founded in 2019 to bring together countries and technology companies to combat extremism.

Attacks on two mosques in Christchurch, New Zealand's second-largest city, in March 2019 left 51 people dead and 40 injured. The white supremacist gunman who carried out the assault live-streamed part of it on Facebook.

"The Christchurch Call is a foreign policy priority for the government and Jacinda Ardern is uniquely placed to keep pushing forward with the goal of eliminating violent extremist content online," Hipkins said in a statement.

"Terrorist and violent extremist content online is a global issue, but for many in New Zealand it is also very personal."

Ardern became the youngest female leader in the world when she won power in 2017 at the age of 37, in a wave of popularity dubbed "Jacindamania". (Reporting by Alasdair Pal in Melbourne; Editing by Tom Hogue)