Australian Brenton Tarrant, 28, has been charged with one count of murder and is likely to face more before he returns to court on April 5.
Ms Ardern has vowed to change New Zealand's gun laws after confirming Tarrant had obtained a Category A gun licence in November 2017 and "under that, he was able to acquire the guns that he held".
"The problem is that it's not new", said Imam Yousef Wahb before mid-afternoon prayers.
She did not offer too much detail, but said a ban on semi-automatic weapons would be looked at.
"We are happy and grateful that the police are taking preventative steps, proactively coming forward to help us ... it's more of a reassurance to the community that we're looking forward".
He said the gunman was white and was wearing a helmet with some kind of device on top, giving him a military-type appearance.
"We stand in solidarity with the people of New Zealand and their government against this vicious act of hate". The suspect appeared to be a white supremacist motivated by US -based extremism, having posted a manifesto online declaring his hatred for Muslims and idolizing USA extremist movements.
Many of you will have seen that Air New Zealand has cancelled all turboprop flights out of Christchurch tonight and will review the situation in the morning. The live-streamed massacre received a flurry of "likes" and positive comments from New Zealanders on the extremist website it was originally posted on.
Muslims account for just over 1 percent of New Zealand's population, a 2013 census showed, most of whom were born overseas.
The video showed a man driving to the Al Noor mosque, entering it and shooting randomly at people with a semi-automatic rifle with high-capacity magazines. She called the shootings a terrorist attack, one that appeared to have been well planned.
New Zealand's Minister for Pacific Peoples Aupito William Sio said he spoke to one of the Trustees of the Festival last night about the decision, and why it was made.
Two other people have been arrested in connection with the terror attack, and they remain in custody as police conduct an ongoing investigation as to their possible involvement.
"Its important to be here standing with you because as Prime Minister Ardern said yesterday, an attack against one is an attack against all of us", Mr Morrison told reporters. In New Zealand, commentators also anxious that the horror would sow deep divisions in a society that has largely avoided the polarizations that have spread elsewhere. Tarrant did not apply to have the judge suppress his name from the media, Australian broadcaster ABC reports. Versions of the video reportedly persisted on the sites for hours after the shootings.
Windsor's Muslim community came out in their usual numbers for Friday prayers, shaken this week, however, by the horrific terrorist attack on the other side of the globe earlier in the day but standing steadfast in their resolve to maintain their way of life.
Leaders around the world expressed sorrow and disgust at the attacks, with some deploring the demonisation of Muslims.
Ardern was asked if she agrees with Trump's remarks that white nationalism is not on the rise. "I blame these increasing terror attacks on the current Islamophobia post-9/11", Pakistani Prime Minister Imran Khan posted on social media.