At one point he gazed around at the courtroom, which was packed with media.
The public was barred from the court for reasons of safety, Judge Kellar said.
Brenton Harrison Tarrant has not applied for bail or for the suppression of his name.
The gunman is believed to have killed 41 people at the Al Noor mosque before driving about five kilometres across town and attacking the Linwood mosque, where he killed seven more people.
"Both my wife and I were utterly horrified to hear of the most barbaric attacks on two mosques in Christchurch", the statement reads. Police said more charges would follow.
The attack has prompted an outpouring of grief and deep shock in this usually peaceful and hospitable country, which prides itself on welcoming refugees fleeing violence or persecution.
Tarrant has been identified as a suspected white supremacist, based on his social media activity.
The gym's owner, Tracey Gray, described him as a hard-working trainer but said he appeared to have been changed by his travels in Europe and Asia - which social media posts suggested included trips as far afield as Pakistan and North Korea.
Police Commissioner Mike Bush also praised the officers who brought the massacre to a halt.
"If Jacinda Ardern moves as quickly as [former Australian prime minister] John Howard did [when he banned guns following the 1996 Port Arthur massacre], and she does it in 12 days, the probability is that she will be able to do what she wants to do", Alpers told the Guardian.
New Zealand's Prime Minister Jacinda Ardern. Credit PA
The man facing murder charges was an Australian citizen who had spent a lot of time travelling overseas and spent time only sporadically in New Zealand, Ardern said.
"New Zealanders are devastated", Jackson said in a statement to Variety.
Hungry for any news, families and friends of the victims gathered at the city's Hagley College, near the hospital. This is a partial transcription of those press conferences in which she touches on her country's diversity, sending condolences to victims and their families and communities.
A Saudi man, Mohsin Al-Mozaini was among the dead, AlArabiya reported.
According to the National Terrorism Threat Advisory System, this would mean authorities have received "credible intelligence that indicates that individuals or groups continue to possess the intent and capability to conduct a terrorist attack in Australia".
Radio New Zealand quoted a witness inside the mosque saying he heard shots fired and at least four people were lying on the ground and "there was blood everywhere". Police said the alleged shooter was arrested in a auto, which was carrying improvised explosive devices, 36 minutes after they were first called.
The Bulgarian government has also said it was looking into Tarrant, who apparently visited the country late past year, as well as having earlier travelled to other parts of the Balkans - including Serbia, Croatia, Montenegro and Bosnia and Herzegovina. Facebook, Twitter and YouTube all said they had taken steps to remove copies of the videos.
Ms Ardern spoke with victims of the sickening terror attack.
Christchurch is a city of about 400,000 residents, still recovering from a massive natural disaster in 2011 that killed 187 people.
I have spoken this evening to the mayor of Christchurch and I intend to speak this evening to the Imam. It's a city in crisis mode yet again, just a few years on from the quakes that rattled Christchurch to its core.
Two men and a woman, including a man in his late 20s who was charged with murder, were in custody last night.
Declan Rice: Gareth Southgate says dual nationality is 'complicated' issue
We have a few in our squad, but in the end, mentality often dictates how far players can go. On Rice call-up: "We've tracked him for quite a while".
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