The National Remembrance Event for the March 15 terror attack has been cancelled due to coronavirus.

The National Remembrance Event for the March 15 terror attack has been cancelled due to concerns about tracking those in attendance if someone was later found to have coronavirus.

A large crowd, including many who travelled to New Zealand from overseas, was expected at Sunday's national event in Christchurch to mark one year on from the attacks on two mosques that took 51 lives.

Authorities said a major reason the event was cancelled was because it would not have been possible to track those who were at the unticketed event if someone with coronavirus did attend.

STACY SQUIRES/STUFF Tony Green, media spokesman for Masjid An-Nur (also known as the Al Noor Mosque) responds to questions from the media on the event's cancellation.

Prime Minister Jacinda Ardern said while there was still no community transmission of coronavirus in New Zealand, a precautionary approach was being taken to protect the health of all New Zealanders.

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She said it was a "pragmatic decision".

STACY SQUIRES/STUFF The event to mark the one year anniversary of the Christchurch terror attacks at two mosques has been cancelled. (File photo).

"We're very saddened to cancel, but in remembering such a terrible tragedy, we shouldn't create the risk of further harm being done.

"The advice we received for this event, is that based on people travelling from different parts of the country and from overseas, if there was a case it could be difficult to trace those who had come into contact with that person, so we are taking a cautious approach."

Ardern said March 15 had now become "an opportunity for every New Zealander to reflect in their own way on the events of a year ago", and to recommit to the values of inclusion and love demonstrated so clearly after the attacks.

STACY SQUIRES/STUFF Minister Megan Woods (L) and Christchurch Mayor Lianne Dalziel explain why the National Remembrance Event has been cancelled.

Tony Green, media spokesman for Masjid An-Nur (also known as the Al Noor Mosque) said they accepted that the event was cancelled over health concerns.

"Our consistent position is with regards to security we take police advice, and it would be unwise not to take health advice on this."

Green said it was said in Islam that every action is to be judged by its intention, and the intention of the cancellation was to look after the health of the community.

Christchurch Mayor Lianne Dalziel said it would not be possible for the planned speeches to be televised at this late stage, but expected they would be able to be published in written form on Sunday.

She said it would have been hard for people not to hug each other had the event gone ahead.

"I think if it had been something else, it's much easier to stand back, but your heart naturally goes out to people and there is a desire and a need to embrace, and ... that creates a risk situation."

Greater Christchurch Regeneration Minister Megan Woods said there were two main reasons the event had been cancelled: because of the large number of people travelling within New Zealand, and some from overseas, to attend, and because there was no way to trace who was there if someone was later found to have coronavirus.

Woods said the Ardern would no longer be travelling to Christchurch on Sunday.

Both Woods and Dalziel endorsed the Christchurch Invitation, an initiative encouraging people to "spread peace, reconnect and feed the hungry" to create lasting change in the wake of March 15.

The remembrance event was planned for Horncastle Arena, and would have featured speeches from the imams of the Linwood and An-Nur (or Al Noor) mosques, a short film, several musical performances, and an address from Ardern.

The cancellation was announced at about 1pm on Saturday. A sixth case of coronavirus in New Zealand was confirmed in Auckland at that time. There were currently no confirmed cases in Christchurch.

A remembrance event in Auckland has also been cancelled.