Tarrant's uncle, Terry Fitzgerald, said they learned of his role in the massacre at two mosques in Christchurch from the television.
The judge said "it was reasonable to assume" more such charges would follow. He remained silent throughout the appearance but made a hand gesture associated with white supremacists.
In online forums, people discussed Muslim food restrictions as they prepared to drop off meals for those affected.
Referenced are Alexandre Bissonnette, who was sentenced to life in prison for the Quebec mosque shooting in 2017, and Luca Traini, who gunned down black immigrants in central Italy a year ago. 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. An officer stopped him.
Flowers and a New Zealand national flag are seen at a memorial as tributes to victims of the mosque attacks near Linwood mosque in Christchurch, New Zealand, March 16, 2019.
Police said the alleged shooter took seven minutes to travel to the second mosque in the suburb of Linwood, where seven people were killed.
One student, who asked not to be identified, said a friend had been killed.
Two Indonesians, a father and son, were also among those shot and wounded, Foreign Ministry spokesman Arrmanatha Nasir said. The shooter fires hundreds of rounds of bullets inside and outside Al Noor Mosque, where the majority of the bloodshed occurred, retreating at one point to his vehicle for another weapon. They have not heard from him since.
7 Indians, 2 of Indian origin still missing after New Zealand mosque shootouts
With 49 people killed in the mosque attacks, it was by far the deadliest shooting in modern New Zealand history.
"How can it be right for this atrocity to be filmed by the murderer using a go-pro and live-streamed across the world by social media companies?"
Mohammed Elyan, a Jordanian in his 60s who co-founded one of the mosques in 1993, was among those wounded, as was his son, Atta, who is in his 30s, according to Muath Elyan, Mohammed's brother, who said he spoke to Mohammed's wife after the shooting. Police also defused explosive devices in a vehicle. About two dozen men received instructions on their duties Sunday, which included Muslim burial customs.
Australian police said the family of the suspect is helping their investigation.
"I want to reassure all New Zealanders that we are doing absolutely everything in our power to respond to this attack, and deploying all available resources in communities across New Zealand", Bush said.
One man was arrested and charged with murder in what appeared to be a carefully planned racist attack. "Our other key priority is making sure that those people so horribly affected by these events get the support and welfare that they need", the New Zealand Police said in a statement. But it has one of the lowest gun homicide rates in the world.
"Our gun law will be changed" said Ardern, noting that the killers had legitimate gun license.
Ardern said Tarrant had five guns and a firearms licence, adding: "Our gun laws will change". Neighboring Australia has virtually banned semi-automatic rifles from private ownership since a lone gunman killed 35 people with assault rifles in 1996.
Turkish leader shows NZ attack video at rallies
He made the comments in Canakkale province, northwestern Turkey which is home to the historic battlefields, on the anniversary of a World War I Turkish naval victory.