Prime Minister Jacinda Ardern and Police Commissioner Mike Bush are giving a statement on the mosque shootings.
Watch Jacinda Ardern speaking to media:
Forty-nine people died at Al Noor Mosque next to Hagley Park and the Linwood Masjid Mosque.
Ms Ardern told media this morning she has just been briefed by intelligence officials.
She confirmed there are 49 people dead and over 40 were being treated in hospital, two of these people were in critical condition.
She also confirmed a five-year-old was transferred to Starship Hospital - the only transfer that had taken place.
Ms Ardern said work was underway to confirm the identities of those who have died but that all those who were injured had been identified and their families told.
She said Christchurch Hospital is well equipped and coping well and that pathologists had made themselves available, and a number were coming in from Australia.
Ms Ardern said three people have been arrested in relation to the attacks and an Australian will appear in court today.
"This individual has travelled around the world, with sporadic periods of time spent in New Zealand. They were not a resident of Christchurch, in fact they were currently based in Dunedin at the time of this event," she said.
Inquiries are ongoing to establish whether the other two arrested were directly involved.
A fourth person was a member of the public who was armed but had the intention of assisting the police. They have been released.
The prime minister said police were working to build a picture of those in custody.
"None of those apprehended had a prior criminal history either here or in Australia," she said. "They were not on any watchlists here or in Australia."
Agencies have been asked to work swiftly to assess whether there were any posts on social media that should have triggered a response.
"Today as the country grieves, we are seeking answers," Ms Ardern said.
Talking about the weapons used, she said she was advised that there were five guns used by the primary perpetrator.
"There were two semi automatic weapons and two shotguns. The offender was in possession of a gun license, I'm advised that this was acquired in November of 2017. A leather action firearm was also found."
Ms Ardern said the safety of New Zealanders the biggest priority.
"I can tell you right now our gun laws will change."
Christchurch residents have been asked to remain at home.
Armed police remain at a cordon near the Masjid Mosque in Linwood, Christchurch, this morning.
The corner of Hereford Street and Linwood Avenue remains closed to the public with closed signs, emergency tape and orange cones blocking access.
Ms Ardern said 45 additional police staff have flown to Christchurch with over 80 flying in today. Detectives, public safety teams and intelligence support are among the police staff.
Ms Ardern urged anyone in New Zealand to call or text 1737 if they are feeling distressed.
She reiterated calls from the police not to distribute material, like videos, related to the attack and stated that it is an offence to do so.
Yesterday police immediately secured the area, arrests were made swiftly and Defence quickly made improvised explosive devices safe, Ms Ardern said.
Mosques around the country have received advice from police about staying safe and have been told to stay closed.
Ms Ardern said the threat level remains at high and as such triggers increased aviation and border security.
A number of specialist family liaison staff have been deployed and the wider government will be working with leaders and members of the wider muslim community to provide assistance, reassurance and support.
Wally Huamaha and 15 ethnic liaison officers are assisting to repatriate loved ones in a way that is consistent with muslim beliefs while taking into account specific circumstances and obligations to the coroner, Ms Ardern said.
She is now flying to Christchurch on a Defence Force plane with leader of the opposition Simon Bridges and other political leaders.
Ms Ardern yesterday said it was "clear this was one of New Zealand's darkest days".
She said the attack is an extraordinary and unprecedented act of violence.
"These are people that I would describe as having extremist views, that have absolutely no place in New Zealand and in fact have no place in the world."