The man accused of the attacks, 29-year-old Australian white supremacist Brenton Tarrant, live-streamed the it to Facebook. The clip was downloaded and shared online thousands of times before it could be removed.

In the weeks that followed what was called one of New Zealand's "darkest days", Prime Minister Jacinda Ardern led the charge to ban the use of the country's deadliest types of semi-automatics, and in a nationwide buyback, gun owners turned in about 60,000 weapons.

In the months that followed, the New Zealand prime minister successfully rallied several countries and companies - including Facebook - to sign the Christchurch Call, intended to pressure the largest internet platforms to eradicate violent and extremist content.

New Zealand High Commissioner Dame Annette King said she believes the prime minister's words at parliament in Wellington hours after the attack, when she told cameras that New Zealand was a "home for those who share our values, refuge for those who need it" resonated around the world.

Dame Annette will speak alongside the ACT minister for multicultural affairs Chris Steel at Canberra Nara Peace Park on Sunday.

The event was scaled down on Friday following the federal government's recommendation to limit gatherings of more than 500 people to reduce the risk of coronavirus.

What had been planned as a public memorial in the ACT was downgraded to just include officials involved.

The announcement preceded a decision by Christchurch City Council on Saturday to cancel its Sunday service as a precaution to contain the spread of coronavirus.

Dame Annette said if anything had changed after the 2019 attack it was improved relations between New Zealand and its "closest friend and neighbour" Australia.

"What was very obvious to us was the outpouring of love, support and solidarity from our Australian mates," she said.

Dame Annette said the opening up of mosques across New Zealand and Australia brought communities together.

"There was an opening up and an understanding that these people were New Zealanders. The grief and sorrow for our Muslim populations really shone through," she said.

Dame Annette said the purpose of the event on Sunday was to come together to grieve and extend deep sorrow to the Muslim community.

The memorial also included the Australian National University's NZ Club, who rang the park bell 51 times for those who died in the Christchurch attack.

Tarrant is due to stand trial in June on charges of terrorism, murder and attempted murder. If found guilty, he would face a sentence of life imprisonment.