The building had closed so police could investigate the attack but on Saturday small groups were allowed to return.
Fifty people were killed in shootings at two mosques on 15 March.
As the Al Noor mosque reopened, some 3,000 people walked through Christchurch on Saturday for a ‘march for love’ intended to honour victims.
Many walked in silence and some carried placards calling for peace and opposing racism.
“We feel like hate has brought a lot of darkness at times,” said Manaia Butler, a 16-year-old student who helped to organise the march. “Love is the strongest cure to light the city out of that darkness,” she said.
Aden Diriye, who lost his 3-year-old son in the attack, returned to the Al-Noor mosque on Saturday. “I am very happy,” he said after praying. ” I was back as soon as we rebuilt, to pray.”
Australian Brenton Tarrant, a 28-year-old self-proclaimed white supremacist, has been charged with one murder in connection with the attacks and he is expected to face further charges.
Bullet holes gone, walls repainted
With the crime scene investigation completed, the Al-Noor mosque, where the majority of the victims were killed, was handed back to the city’s Muslim community.
At around midday local time (23:00 GMT Friday), small groups of worshippers were allowed back onto the grounds, while armed police patrolled the site.
“We are allowing 15 people at a time, just to get some normality,” Saiyad Hassen, a volunteer at the mosque, told AFP news agency. He did not say when the mosque would fully reopen.
The mosque had been repaired, with bullet holes filled in and walls freshly painted – though the lack of rugs on the floor served as a reminder of what had happened.
Worshippers knelt to pray on a grey padded carpet underlay taped to the floor.
“It is the place where we pray, where we meet, we’ll be back,” Ashif Shaikh, who was in the mosque at the time of the shooting, told Reuters news agency.
Police said the nearby Linwood mosque, which was the second to be attacked, had also reopened.