Some rushed to their trusted online dealers and stores to stock up on semiautomatic assault rifles.
Despite having tightened the rules in the 1990s after the last mass shooting, New Zealand has relatively permissive gun laws, with almost all of those who apply granted gun licences. Leaders have hinted the changes will impact the proliferation and availability of semiautomatic weapons in particular.
Friday's events sparked calls for gun law reform, with Ms Ardern saying soon after that "our gun laws will change". Details of the changes will be announced within the week, and must be passed by parliament.
"We believe absolutely there was only one attacker responsible for this", Bush said at a news conference. Licences of gun dealers must be renewed annually.
Ardern, the youthful premier who has become the face of the nation's tragedy, said there would be an inquiry into the horrifying attack, as questions swirl over whether intelligence agencies should have spotted warning signs.
The owner of a New Zealand gun store the man charged with murder in the mosque shootings had bought firearms and ammunition online from the store, but it did not sell him the high-powered weapon used in the massacre.
Morrison said that social media companies had "co-operated" since the attack. "We need a constant supply as blood that's donated can't be used after 35 days", a media spokesperson of the organization said. Video of the gunman in the mosque showed a semi-automatic with a large magazine round.
"These people died in prayer, on their way to prayer, on our holy day, a Friday, in the precincts of our holy places", said Rehanna Ali, from the Federation of Islamic Associations of New Zealand. "We are not a country of emotional responses, we are a country with laws [and] what we are doing is legal".
"It's good for the world to see what's happened because people around the world, they thought we were terrorists because some stupid people, they said they are Muslims, they go and kill innocent people", said Abulaban, who migrated to New Zealand from Jordan 17 years ago. "How, in 2019, can this still be going on?"
Previous attempts to tighten gun laws in New Zealand have failed due to a strong gun lobby and a culture of hunting. That rate is much lower than the rate in the US, where some estimate there are more guns than people.
Still, New Zealand has made the decision in nearly record time.
"When Australia found itself tragically in a similar position to what we find ourselves now, they took 12 days to make their decision". It took nearly two years for the ban on handguns to become law in the United Kingdom in 1998.
Ardern was the first signatory of a national condolence book that she opened in the capital, Wellington. Until Friday, the country's worst mass shooting was in 1990, when a gunman killed 13 people in the small town of Aramoana.
Earlier Monday, popular New Zealand e-commerce website TradeMe ended the sale of semi-automatic guns on its online marketplace.
These suggestions, said Philip Alpers, an adjunct associate professor at the University of Sydney and founding director of GunPolicy.org, "are all now back on the table". Many came together for a haka - a traditional Maori ceremonial dance that has been performed by groups across New Zealand in the wake of killings.