Police said on Thursday that other charges are still under consideration.
He was charged at the time with one count of murder and remanded in custody without a plea.
Brenton Tarrant appeared at the High Court in Christchurch via a video link from an Auckland prison.
Fifty people, including five Indians, were killed and many others injured as they attended Friday prayers at two mosques on March 15.
Mr Tarrant entered the two mosques armed with high-powered weapons and streamed the attacks via Facebook live.
New Zealand Prime Minister Jacinda Ardern called the attack "one of New Zealand's darkest days", and less than a week later announced plans to ban almost all military-style semi-automatic and assault-style rifles.
In comments that were later admonished by New Zealand Foreign Minister Winston Peters, Erdogan said, "If the New Zealand Parliament doesn't make this decision I will continue to argue this with them constantly".
The High Court Judge said nothing should be read into his order for the mental health assessments, as it was a standard step in such a case. "So I wanted to see how he feels after killing 50 innocent people".
Journalists gather outside the Christchurch District Court ahead of alleged gunman Brenton Tarrant's appearance for his hearing via audio-visual link from a maximum-security prison in Auckland.
Justice Cameron Mander formally recorded that a further 49 charges of murder and 39 of attempted murder had been filed by the Crown.
"What Have They Found?" ESO to Reveal Epic Black-Hole Discovery
But the telescope hopes to capture an image of the event horizon - the point at their edge where light can not escape. These monsters consume everything near them with gravity so intense that even light can't escape.
Families in the court cried quietly as Tarrant appeared on screen, handcuffed with his hands in front of him.
Also, the Terrorism Suppression Act 2002 has seldom been used and most prosecution lawyers have little working knowledge of it.
He's received a murder count for each of the victims who died in two mosques in Christchurch as well as 39 counts of attempted murder.
"I didn't see any emotion on his face", Tofazzal Alam, who survived the attack on the Linwood mosques told reporters afterwards.
Home Affairs secretary Michael Pezzullo, who is responsible for most of the country's security and intelligence edifice, said the accused gunman had spent just 45 days in Australia during the past few years.
Tarrant had sacked his court appointed lawyer last month, saying he would represent himself.
The New Zealand Herald reported that the hearing will be largely procedural and will involve scheduling future dates allocated by the judge.
He has no access to television, radio, newspapers or visitors.
New Zealand is in the process of tightening its gun laws after the attack and the government has also said it will review laws dealing with hate speech.
Comments