The man, who was arrested on Friday, was not involved in the attacks on the two mosques that killed 50 people and injured dozens more.
Shooting suspect Brenton Tarrant, 28, has already appeared in court where he was pictured smirking and make a 'white power' symbol.
If the teenager, who is back in court in April, is found guilty he could face up to 14 years in behind bars.
Tarrant is also back in court next month and could represent himself after it was revealed he had sacked his duty lawyer.
Richard Peters told the New Zealand Herald that the accused gunman had told him he wanted to represent himself in the future.
It has raised concerns that the Australian could try and emulate Charleston church shooter Dylann Roof.
White supremacist Roof - who Tarrant referenced in his twisted manifesto - also represented himself in court.
The cowardly attack on two mosques in Christchurch during Friday prayers was the deadliest mass shooting in New Zealand's history.
Facebook took down 1.5 million copies of footage of the shooting that had been livestreamed by Tarrant in the 24 hours after the carnage.
Prime Minister Jacinda Ardern said she had contacted Facebook's chief operating officer to voice her concerns about the sharing.
She told reporters: "I haven't spoken to her directly but she has reached out, an acknowledgment of what has occurred here in New Zealand.
"This is an issue that I will look to be discussing directly with Facebook."