About 15,000 turned out for an evening vigil in Christchurch in a park near the Al Noor mosque, where a suspected white supremacist killed more than 40 of the victims. Several more people were killed at the nearby Linwood mosque.
The crackdown applies to new gun purchases but also effectively rendered illegal the targeted weapons already in the hands of New Zealanders.
New Zealand police found a suspected bomb and ammunition on Tuesday in a vacant lot in Christchurch, the scene of last month's mosque shootings which killed 50 Muslim worshippers.
The special visa category "recognises the impact of the tragedy on the lives of those most affected, and gives people currently on temporary and resident visas some certainty" about their status, Immigration New Zealand said in a statement.
Drone images showed worshippers standing in formation, their snow-white traditional shalwar kameez and prayer caps in stark contrast to the emerald green of a public field, as a second group formed the words "Islam is peace" nearby.
The Muslim community was further shaken this week when a 33-year-old man, wearing a t-shirt emblazoned with the name of US President Donald Trump, shouted abuse at worshippers at the Al Noor mosque.
The Australian man accused of killing 50 Muslim worshippers in gun attacks on two mosques in Christchurch will face 50 murder charges and 39 attempted murder charges,
: A far-right Australian senator who said the Christchurch mosque massacre was the result of Muslim immigration into New Zealand was censured for his “ugly and divisive” comments by his parliamentary peers on Wednesday.