Anguished relatives are anxiously waiting for authorities to release the remains of those who were killed in massacres at two mosques in the New Zealand city of Christchurch, while authorities announced the death toll from the attacks had risen to 50.

Islamic law calls for bodies to be cleansed and buried as soon as possible after death, usually within 24 hours.

But two days after the worst terrorist attack in the country’s modern history, relatives remained unsure when they would be able to bury their loved ones.

Police Commissioner Mike Bush said police were working with pathologists and coroners to release the bodies as soon as they could.

“We have to be absolutely clear on the cause of death and confirm their identity before that can happen,” he said.

“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 relatives who were waiting for any news.

The scale of the tragedy and the task still ahead became clear as supporters arrived from across the country to help with the burial rituals in Christchurch.

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

CORRECTION New Zealand Mosque ShootingMourners lay flowers on a wall at the Botanical Gardens in Christchurch, (Vincent Thian/AP)

Mr Bush said at a news conference on Sunday that they found another body at Al Noor mosque as they finished removing the victims, bringing the number of people killed there to 42.

Another seven people were killed at Linwood mosque and one more person died later at Christchurch Hospital.

Another 34 victims remained at Christchurch Hospital, where officials said 12 were in critical condition. A young child who was in a children’s hospital in Auckland was also listed as critical.

Dozens of Muslim supporters gathered at a centre set up for victims, families and friends across the road from the hospital, where many had flown in from around New Zealand to offer support and authorities sent in diggers to prepare new graves in a Muslim burial area that was newly fenced off and blocked from view with white netting.

About two dozen men received instructions on their duties on Sunday morning, which included Muslim burial customs.

New Zealand Mosque ShootingA message card is placed at a collection of flowers left at the Botanical Gardens in Christchurch (Vincent Thian/AP)

Abdul Hakim, 56, of Auckland, was among many who had flown in to help.

“As soon as people die we must bury them as soon as possible,” Mr Hakim said. “We are all here to help them in washing the body, putting them in the grave.”

Javed Dadabhai, who flew from Auckland after learning about the death of his 35-year-old cousin Junaid Mortara, said the Muslim community was being patient.

“The family understands that it’s a crime scene. It’s going to be a criminal charge against the guy who’s done this, so they need to be pretty thorough,” he said.

People across New Zealand were still trying to come to terms with the massacre that Prime Minister Jacinda Ardern described as “one of New Zealand’s darkest days.”

A steady stream of mourners arrived at a makeshift memorial outside the Al Noor mosque, where hundreds of flowers lay piled amid candles, balloons and notes of grief and love.

Under a nearby tree, someone had left a potted plant adorned with cut out red paper hearts.

“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. We made a heart for you. 50 hearts for 50 lives.”