The government told the public that setting up an over-arching intelligence and security agency was still under "active consideration", when it had already decided to dump it, documents show.
Setting up a super-agency was central to six of the first 10 recommendations of the Royal Commission of Inquiry into the 2019 mosque attacks, but it was confirmed last week that it was one of eight recommendations that will not be progressed.
Judith Collins' office told RNZ on 7 May the agency was "currently under active consideration and is going through the Cabinet process", with any decisions to be announced "in due course".
But newly-released documents show the Prime Minister had already decided by April to dump it.
"A National Intelligence and Security agency will not be established," said a 19 April briefing to Collins, the minister in charge of responding to the recommendations.
"The Prime Minister has decided to maintain the current arrangement whereby the CE [chief executive] of DPMC [Department of Prime Minister and Cabinet] leads the government's national security function.
"These decisions are the least disruptive and avoid the need to create the infrastructure of a new agency, thereby streamlining rather than adding to complexity to the system."
In a statement, Collins told RNZ this week the National Intelligence and Security agency (NISA) was still under active consideration until Cabinet confirmed it on 1 July.
"Decisions are not final until they have been approved by Cabinet," she said.
She said it was not a matter of cost.
"I acknowledge we are in a fiscally constrained environment. However, this was not the driver for the decisions ministers made on the remaining recommendations.
"In making these decisions, the government's primary consideration was whether the overarching intent of the [royal commission] - to make New Zealand safer and more secure - was being met."
The Royal Commission found the web of national security agencies led by the DPMC was blind to the far right, fixated on Muslims, underperforming and siloed prior to the March 2019 attacks.
Its recommendations found it was important that a NISA was more independent.
The Kāpuia ministerial advisory group told the government on 28 May it wanted a NISA set up, and a "strong monitoring, performance and oversight mechanisms in place for national security agencies".
Luxon's rationale was that enough changes had been made within DPMC since 2020 to strengthen oversight, by separating two core functions and through a "series of mechanisms to drive the performance required".
"Changes have been made in DPMC... in line with DPMC recommendations," the April briefing said.
The papers - 147 pages worth - were released by the DPMC on Friday, the same day the government announced it was concluding the all-of-government response to the mosque attacks, and dumping eight of the 44 recommendations that Jacinda Ardern's government had pledged to implement.
The papers showed Collins first moved in December to wrap up the overall response.
A new NISA - the closest New Zealand could get to a US-style national security agency - was meant to implement five of the first 10 recommendations, including setting up an advisory board on counterterrorism.
That advisory board has also been dumped, because Luxon judged it "would not yield sufficient benefits to warrant the administrative burden, and overheads".
Elsewhere, the papers refer to the "fiscal environment" as a reason for rejecting another recommendation, on restorative justice.
A new system for the public to lodge reports about extreme or disturbing behaviour was also binned. The national security section of DPMC told ministers that other mechanisms for hearing about these had "significantly increased and improved" recently.
An assessment in mid-2023 said the reporting system would address "current gaps in how these agencies understand threats and remove information siloes".
The police completed a $1m business case on setting up a reporting system last August, the same month the previous government said a NISA was close to being set up.
The DPMC recently delivered a plan to the government to save $3.2m under the public sector cost-cutting drive, including by halving the funding of research into violent extremism that some critics say has not been very effective.