Prime Minister Jacinda Ardern has vowed to unveil gun law reforms within 10 days and announced a review into security agencies after the mosque shootings.
Cabinet met today and had made an in-principle decision about changes to gun laws.
"As a Cabinet we were absolutely clear, the terror attack on Friday was the worst act of terrorism on our shores," she said.
The mosque shootings had highlighted weaknesses in our gun laws and these would be addressed, she said.
Ardern also confirmed there would be a review of security agencies' actions in the wake of the shooting.
It would look at what they knew, or should have known, and whether there were any blocks to information-sharing.
The review would also probe accused gunman Brenton Tarrant's travel and use of social media.
The terms of reference were being finalised and the review would include the Security Intelligence Service, Government Communications Security Bureau (GCSB), police, Customs and Immigration.
The GCSB said it welcomes the inquiry into the Christchurch terrorist attacks.
“The attacks on Friday were an abhorrent challenge to everything that New Zealand holds dear," said GCSB director Andrew Hampton.
“As primarily a foreign intelligence and cyber security agency, the GCSB's role in domestic counter terrorism is to support Police and NZSIS as required and pass on any relevant intelligence received from partners.
“GCSB is normally in a position where it can neither confirm nor deny any operational details, but given the nature of the situation I can confirm GCSB had not collected or received from partners any relevant intelligence ahead of the terrorist attacks.
“New Zealand’s intelligence and security agencies do not currently have the legal authority, technical means or resources to actively monitor all online activity that occurs in New Zealand. In addition, all intelligence and security agencies are grappling with the challenges of encryption and closed online communities.
"“It is important that there will be the inquiry and GCSB is committed to providing all necessary support."