The city of Christchurch has come together in mourning following an attack, which saw a lone gunman open fire on worshippers in a mass shooting at two mosques in the community on Friday.

On the grass outside a church in the New Zealand city, lie 50 pairs of white shoes, each representing one of the lives lost in the recent attack.

"One of the sort of things we were aware of was the tradition of taking off your shoes as you went in to worship," said the Vicar of All Souls Church, Megan Merles-Mooar.

"And suddenly the thought that there were 49 and 50 pairs of shoes that would never be filled again, was just an image that just kept coming back."

Shoes were donated by members of the public and painted white by a church volunteer.

With preparations for the first burials under way, New Zealand's Prime Minister Jacinda Ardern praised the bravery and courage by mosque worshippers, saying the nation stood with its grieving Muslim community in this "darkest of days".