Handcuffed and wearing a white prison suit, Tarrant did not speak.
The victim can not be named by order of the court.
Muslims hold placards after a prayer meet for victims of Friday's mosque attacks in New Zealand, outside a mosque in Jammu March 16, 2019.
Former NSW personal trainer Tarrant did not apply for bail when he appeared in court on Saturday and was remanded in custody without plea until April 5.
New Zealand Police Commissioner Mike Bush announced the latest death in a news conference Sunday.
The President of French Polynesia, Edouard Fritch sent a message of support to New Zealand Prime Minister Jacinda Ardern, following the attack in Christchurch. "Police will continue to maintain a presence at all Mosques across New Zealand", New Zealand Police tweeted on Sunday.
"I have asked our agencies this morning to work swiftly on assessing whether there was any activity on social media or otherwise, that should have triggered a response". The manifesto, titled "The Great Replacement", also stated that "the invaders must be removed from European soil, regardless from where they came or when they came".
"We deeply mourn loss of all other innocent lives including people of Indian origin".
The revelation comes as relatives of those murdered in New Zealand continued to endure an agonising wait for confirmation of the identities of those killed in Christchurch, New Zealand.
"The terrorist attack appeared to have been carried out by a white nationalist who posted a racist manifesto online and streamed live video of the killings on Facebook", reports The New York Times. Worshippers, possibly dead or wounded, lay on the floor, the video showed.
Mr Bush said four other people arrested during Friday's police operation have either been released or charged with "tangential" offences.
Armed police were deployed at several locations in all cities, unusual in a country where levels of gun violence are low.
Ardern said Tarrant was a licensed gun owner who allegedly used five weapons, including two semi-automatic weapons and two shotguns, which had been modified. A couple apprehended at a cordon for carrying firearms not believe to be involved in the attacks, Bush said.
New Zealand's attorney general, David Parker, took it step farther and vowed to ban semi-automatic guns at a vigil on Saturday, but later backtracked as reported by The New York Times.
Tarrant did not have a criminal history and was not on any watch lists in New Zealand or Australia.
Police stand guard at Christchurch Hospital.
Police said three people were in custody including a man in his late 20s who's been charged with murder.
A host of world leaders, including US President Donald Trump and UK Prime Minister Theresa May, expressed sorrow and disgust at the attacks.
New Zealand Prime Minister Jacinda Ardern has reiterated her promise that there will be changes to the country's gun laws in the wake of a terrorist attack on two mosques and said her Cabinet will discuss the policy details on Monday.