New Zealand Police have tweeted that other charges are still under consideration.
He said media could still use pixelated images of Tarrant which the district court judge had allowed.
Tarrant did not address the court.
The High Court judge overseeing the appearance ordered Tarrant to undergo a mental assessment to determine whether he was fit to stand trial. It's standard for defendants to be evaluated by two health experts to determine their fitness for trial.
But they would require the consent of the Solicitor-General to lay terror charges against the accused.
Ardern has called for action by social media giants after the alleged gunman live streamed the attacks online.
He was charged at the time with one count of murder and remanded in custody without a plea.
The 28-year-old, a self-confessed white supremacist, sat still with an impassive face during the preliminary hearing, in contrast to his first court appearance when he smirked at the media and appeared to flash a white nationalist hand signal.
Despite the extra security measures, the suspect, who arrived in handcuffs, was pictured making what appeared to be a hand gesture associated with the white supremacist movement.
The attack began at just after 1:30 p.m.at the al Noor mosque in central Christchurch. Police initially filed a single, representative murder charge before filing the additional charges this week. Thousands attended a memorial service in Christchurch a week after the attack, which was also broadcast nationwide.
"It's not going to bring our loved ones back".
Describing the killer as a "coward", Yama said he wanted justice. "I tried to stand strong, to come here, because I don't want my mum to come here to see what he has to say", Nabi said.
The government has also said it will review laws dealing with hate speech.
New Zealand's Department of Corrections said in an email they wouldn't answer questions such as where Tarrant was being held due to operational security reasons. He said reporters could remain throughout and take notes, although would be restricted in what they could report.
"The right to consult and instruct a lawyer and the right to a fair and public hearing are protected rights that the New Zealand Bill of Rights Act provides to every person in this country", Mr Tait wrote. They had been told clearly that he was unable to see them.