The accused, Brenton Tarrant, was not known to any authorities and had no previous convictions, Commissioner Mike Bush said.
Theresa May and Donald Trump were among those who sent messages via social media.
Several major events around the country will not be going ahead today.
1 NEWS Australian Correspondent Ryan Boswell gives the latest update on the Christchurch terrorist attacks from across the Tasman.
"He was live streaming for it what, 17 minutes? Facebook doesn’t close that down, I mean what is going on here," she said.
Mohan Ibrahim has been living in New Zealand for 5 years and says he is scared to live here now.
The PM also instructed agencies to assess if any activity should have triggered a response prior to the attack.
Brother of missing man shown telling police "nobody tells us anything".
The 28-year-old Australian citizen accused of murder appears in Christchurch District Court today.
Brenton Tarrant, 28, has appeared in court charged with murder.
"I simply conveyed the sentiment that exists here in New Zealand."
Fans will be able to show unity after the dark day in New Zealand's history.
So far 14,627 donors have given over $1, 000, 708.47.
Eleven of the 36 patients are in critical condition in the ICU, including a woman in her mid-20s, Christchurch Hospital chief of surgery Greg Robertson said.
Officials decided to call the game at Forsyth Barr Stadium off.
Brenton Tarrant has been charged with murder after yesterday's attacks left 49 dead.
People are gathering for vigils after 49 people were killed during two mosque attacks in Christchurch yesterday.
The PM, Opposition leader, Winston Peters and James Shaw met leaders at a Christchurch refugee centre.
The American intelligence agency is scouring its own databases for potential threats.
Police say they were called to the scene at Rainbow Falls around 2:10pm this afternoon.
The Kiwi led from start to finish in the second race of the Australian GP in Melbourne.
Abdikina Ali-Hassarn was a regular attendee of the Linwood mosque but didn't go to Friday prayers yesterday.
Jacinda Ardern says a "raft of issues" were on the table in upcoming gun law changes.
The team flew out of Christchurch earlier today, arriving at the airport under police escort.
People's fear for loved ones has also been expressed in Christchurch.
Neighbours are shocked and surprised to learn of the connection to the Christchurch attack.
The Warriors ran in seven tries in a 40-6 victory at Mt Smart Stadium.
Brenton Tarrant has been confirmed to 1 NEWS as a member of the Bruce Rifle Gun Club in Milton.
Hundreds gathered on Mount Maunganui Beach at sunset as New Zealanders reached out to support the Muslim community.
