Photo: Contributed

Pope Francis delivers his blessing during the Angelus noon prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, March 17, 2019.

A steady stream of mourners paid tribute Sunday at a makeshift memorial to the 50 people slain by a gunman at two mosques in Christchurch, while dozens of Muslims stood by to bury the dead when authorities finally release the victims' bodies.

Hundreds of flowers were piled up amid candles, balloons and notes of grief and love outside the Al Noor mosque. As a light rain fell, people clutched each other and wept quietly.

"We wish we knew your name to write upon your heart. We wish we knew your favourite song, what makes you smile, what makes you cry," read one of the tributes, which contained cut-out paper hearts under a nearby tree. "We made a heart for you. 50 hearts for 50 lives."

Two days after Friday's attack, New Zealand's deadliest shooting in modern history, relatives were still waiting for authorities to release the bodies. Islamic law calls for bodies to be cleansed and buried as soon as possible after death, usually within 24 hours.

Supporters arrived from across the country to help with the burials in Christchurch and authorities sent in backhoes to dig graves at a site that was newly fenced off and blocked from view with white netting.

Prime Minister Jacinda Ardern said authorities hoped to release all the bodies by Wednesday, and Police Commissioner Mike Bush said authorities were working with pathologists and coroners to complete the task as soon as they could.

"We have to be absolutely clear on the cause of death and confirm their identity before that can happen," Bush added. "But we are so aware of the cultural and religious needs. So we are doing that as quickly and as sensitively as possible."

Police said they had released a preliminary list of the victims to families, which has helped give closure to some who were waiting for any news.

The suspect in the shootings, 28-year-old white supremacist Brenton Harrison Tarrant, appeared in court Saturday amid strict security, shackled and wearing all-white prison garb, and showed no emotion when the judge read one murder charge and said more would likely follow.

Tarrant had posted a jumbled 74-page anti-immigrant manifesto online before the attacks and apparently used a helmet-mounted camera to broadcast live video of the slaughter.

Ardern said the gunman had sent the manifesto to her office email about nine minutes before the attacks, although she hadn't gotten the email directly herself. She said her office was one of about 30 recipients and had forwarded the email to parliamentary security within a couple of minutes of receiving it.

People across the country were still trying to come to terms with the massacre that Ardern described as "one of New Zealand's darkest days."

At the Vatican, Pope Francis offered prayers for "our Muslim brothers" killed in the attack. At his traditional Sunday prayer, Francis renewed "an invitation to unite in prayer and gestures of peace to oppose hatred and violence."

The gunman livestreamed 17 minutes of the rampage at the Al Noor mosque, where he sprayed worshippers with bullets. Facebook, Twitter and Google scrambled to take down the video, which was widely available on social media for hours after the bloodbath.

The second attack took place at the Linwood mosque about 5 kilometres (3 miles) away.

Ardern has said Tarrant was a licensed gun owner who legally bought the five guns he used.

At a news conference, the prime minister reiterated her promise that there will be changes to the country's gun laws. She said her Cabinet will discuss the policy details Monday.