"In short every semi-automatic weapon used in the terrorist attack on Friday will be banned in this country", said Ardern.
Authorities spent four days constructing a special grave at a city cemetery that is designated for Muslim burials.
Ardern previously has said her Cabinet had agreed in principle to tighten gun restrictions in New Zealand and those reforms would be announced next week.
"We are confident as a government that the vast majority of New Zealanders will support this change".
"This will not be popular among some of our members, but after a week of intense debate and careful consideration by our elected representatives and staff, we believe this is the only practicable solution", Federated Farmers Rural Security spokesman Miles Anderson said in a statement.
Both mosques attacked, the Al Noor and nearby Linwood mosque, plan to be reopened.
The burials got under way shortly after the country's prime minister renewed her call to remember the victims rather than the Australian gunman accused of slaughtering them.
Hamza's younger brother Zaed (13) sustained gunshot wounds to the leg in the attack. "I feel incredibly confident of that", she said.
A 44-year-old businessman was remanded in custody after a preliminary court appearance in Christchurch Wednesday on charges of distributing footage of one of the mosque shootings.
Nirav Modi arrested in London, to be produced in court shortly
The 48-year-old Modi was detained Tuesday in central London and held overnight in custody, the Metropolitan Police Service said . A PMLA court in Mumbai has permitted the Enforcement Directorate to sell 173 paintings and 11 cars belonging to Nirav Modi.
Ardern said the attacker used five guns, two of them semi-automatic, and that they were purchased with an ordinary gun licence and modified. "And that's fantastic", said Jamil El-Biza, who traveled from Australia to attend the funeral.
She's also taking seriously a reported call from Islamic State to retaliate, after the jihad group's spokesman was reported in the New York Times as saying the attack should incite caliphate supporters to "avenge their religion".
As of Tuesday night 21 victims had been identified, said police and their bodies would be released for burial.
"We're very much in the dark" on that, she said.
Hart said it was an easy decision for him to hand in his semi-automatic and tweeted: "on the farm they are a useful tool in some circumstances, but my convenience doesn t outweigh the risk of misuse".
"To owners who have legitimate uses for their guns, I want to reiterate that the actions being announced today are not because of you, and are not directed at you", the prime minister said.
Stuart Nash, the minister of police, said they "have no idea" how many assault rifles are in circulation.
Erdogan had already been sharply rebuked by New Zealand for his comments and for using gruesome video shot by the Christchurch mosque gunman as an election campaign prop.
But she pledged that she, and much of New Zealand, would deprive the 28-year-old gunman of the publicity he craved by never uttering his name. Alexandre Bissonnette, in his late 20s, pleaded guilty to six counts of first-degree murder in March 2018, and a year later received a sentence of life in prison with no chance of parole for 40 years.