Brenton Harrison Tarrant, 28, appeared before the Christchurch district court dressed in a white prison jumpsuit, handcuffed and barefoot. He did not speak but appeared to make a white supremacist sign with his hands, the Guardian reported.
He has been charged with one count of murder. Judge Paul Kellar did not reveal the victim’s name on grounds of undue hardship to his family.
He was remanded in custody without a plea and is due appear in court again on April 5.
After Tarrant left the court, Judge Kellar said that while “there is one charge of murder brought at the moment, it is reasonable to assume that there will be others”.
Tarrant, who grew up in the Australian town of Grafton, had been living in the Dunedin, about 360 km south of Christchurch.
New Zealand police closed the Christchurch court to the public over security concerns, but the media was able to attend.
Australian police are investigating Tarrant’s connections around Grafton.
Before his appearance at the court, New Zealand Police Commissioner Mike Bush said Tarrant had been charged with one count of murder, with other charges to follow.
“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.
Tarrant was one of three people arrested in connection with the shootings at the Al Noor Mosque and the Linwood Avenue Masjid on Friday. The other two remain in custody but their role in the shootings remains unclear, CNN said.
A fourth person who had been taken into custody was later determined to be an armed bystander who wanted help police.
Also on Saturday, Prime Jacinda Ardern, while speaking at the Christchurch Canterbury Refugee Centre, showed solidarity with the nation’s Muslim community, saying “this is not the New Zealand people know”.
In her 40-minute address, she also spoke about the importance of reuniting relatives with their loved ones “as quickly as possible”, and said that bodies were still being removed from the Al Noor mosque – the site of the first attack.
She added that financial support would be made available to those who had lost someone on whom they were financially dependent.
Ardern said Tarrant had five guns and a firearms licence, adding: “Our gun laws will change.”
A total of 48 people were wounded in the shootings.
India, Bangladesh and Indonesia all say some of their citizens were killed in the shooting and others are unaccounted for.
Friday’s killing was a terrorist attack that appeared orchestrated for the social media. The brutal shootings were previewed on an infamous Internet message board and then graphically live-streamed on Facebook.
An 87-page manifesto, found by authorities after it was posted online, was filled with anti-immigrant and anti-Muslim ideas.
According to the latest census figures, Muslims make up about 1.1% of New Zealand’s population of 4.25 million.
Numbers rose sharply as New Zealand took in refugees from various war-torn countries since the 1990s.