Brenton Harrison Tarrant entered shock guilty pleas to all 51 murder charges at a special, hastily-arranged High Court hearing in Christchurch on March 26 - the first day of the coronavirus lockdown.
It meant that shooting survivors, victims, and families were unable to be in court that day.
Since then, the justice system has been trying to find a sentencing date post-coronavirus restrictions to accommodate everyone who wants to witness the 29-year-old Australian's final sentencing.
He had been remanded to next Tuesday, which was just a nominal date, in the hope that some finality could be reached and a sentencing date set.
However, in a minute issued by Justice Cameron Mander this morning, the global pandemic and tight border controls and quarantine measures has forced another delay.
The judge says an "acute issue" that has arisen in recent weeks is how to make sure victims and family members who are currently overseas can participate in sentencing, either by travelling to attend in person, or taking part remotely by using audio-visual technology.
"Inquiries are presently being undertaken to ascertain each individual's situation and that of their families who are affected in this way," Justice Mander said.
Once those talks are completed, the courts will assess when an appropriate sentencing date might be.
"That determination will take into account the need to bring finality and closure to the majority of victims who are resident in New Zealand and the extent to which it may be possible for those unable to attend in person because of the pandemic to participate remotely," the judge said.
The defendant has been further remanded to a nominal date of July 13 "pending the completion of the current inquiries".
Along with the murders, the gunman has been convicted on all charges, including 40 charges of attempted murder relating to the two attacks at Masjid Al Noor and Linwood Islamic Centre on March 15 last year - and pleaded guilty to one charge of engaging in a terrorist act laid under the Terrorism Suppression Act 2002.
The Crown's summary of facts, which outlines the offending, will be read out at sentencing.
Justice Mander has called for a pre-sentence report and victim impact statements.
None of the victims knew about March's remarkable, hurriedly-organised hearing.
The city's two imams, Imam Gamal Fouda of Masjid Al Noor and Imam Alabi Lateef from Linwood Islamic Centre, were asked to come to court to witness proceedings on behalf of their Muslim communities.
But even they didn't know what it was going to be about.
After the guilty pleas were entered, Justice Mander explained how the courts –deemed an essential service during lockdown - received an indication from Tarrant's Auckland-based defence lawyers Shane Tait and Jonathan Hudson days earlier saying that he may seek to change his plea to the charges.
The day before, the lawyers received formal written instructions from Tarrant confirming he wanted to change his pleas and court staff started making urgent preparations for the case to be called as soon as possible – while doing so amidst the ramping up of the coronavirus lockdown which came into effect at midnight.
Justice Mander accepted it was "regrettable" to hold the hearing without any victims or family members being present – but said it signalled a "very significant step" in bringing finality to the proceedings.
Temel Atacocugu, who was shot nine times at Al Noor, heard the news from one of the lawyers assigned to assist the victims.
"She called me and asked if I had read the text message," he said.
"I said no and she said the terrorist had changed his plea. I just said 'wow'."
Atacocugu said the pleas were "quite a surprise".
Abdul Aziz Wahabzadah, who threw an Eftpos machine at the gunman in the car park at the Linwood mosque, and chased after him on foot as the shooter sped away by car, said he found out about the guilty plea today via email.
"He's got his right to plead guilty. But I wanted to go to trial to find out why he did it, the reasons behind this nonsense," Wahabzadah said.
"I don't think we will find out now."
Prime Minister Jacinda Ardern earlier said the guilty plea would provide "some relief to the many people whose lives were shattered by what happened on March 15".
"These guilty pleas and conviction bring accountability for what happened and also save the families who lost loved ones, those who were injured, and other witnesses, the ordeal of a trial."
Police Commissioner Mike Bush also welcomed the resolution to what he described as the largest criminal prosecution in New Zealand history.
The two officers who arrested Tarrant, and later received bravery commendations, were said to be relieved at the guilty pleas.
New Zealand's worst-ever act of terrorism was filmed by the shooter and livestreamed on Facebook, leading to gun reforms and a global political summit initiated by Ardern to eliminate terrorist and violent extremist content online.
