Prime Minister Jacinda Ardern is playing down any suggestion a surveillance programme known as Project Speargun could have helped prevent the Christchurch terror attacks.
National leader Simon Bridges yesterday said Project Speargun should be reconsidered following the 15 March mosque shootings which left 50 people dead.
The cyber-snooping proposal to scan internet traffic coming into the country was ditched by the former National government and then-prime minister John Key in 2013.
Speaking at her weekly media conference, Ms Ardern queried any "assumption" that the programme could have increased "knowledge" of the massacre ahead of time.
"That actually may not have been the case, because my understanding of Project Speargun is that it was a cyber-security initiative, rather than maybe what is being implied."
Ms Ardern said the Royal Commission into the shootings would investigate "whether or not [intelligence agencies] could or should have known more".
"New Zealand is not a surveillance state - and that's been a very clear directive, I think, from members of the public," Ms Ardern said.
"But questions of course need to be answered around whether or not these were the activities of an individual that we could or should have known."
Mr Bridges told RNZ he did not know whether Project Speargun could have prevented the terror attack, but it "would've done more to keep New Zealanders safe".
"I'm not saying it would have made the difference [in the case of the shootings]. I certainly don't think you can say it absolutely wouldn't have," he said.
"Our risk profile has changed from low to high and we should be revisiting our security settings. We should be looking at the likes of Project Speargun given the much greater ability it would have to keep New Zealanders safe."
Mr Bridges said Ms Ardern was "fudging and dodging" questions about New Zealand's surveillance laws.
"It may be a hard question for the prime minister, but actually we need and deserve as New Zealanders to understand her position on issues such as our security laws and Project Speargun."
Mosque attack a 'failure of human intelligence' - security consultant
Security consultant Paul Buchanan told Morning Report he disagreed that intelligence agencies have their hands tied behind their backs - something Mr Bridges said on the programme yesterday.
He said a joint review by the Law Commission and the Ministry of Justice in 2018 found that New Zealand's surveillance laws struck a good balance between privacy and security.
"In fact [the spy agencies] have more powers than anytime previously."
Problems that led to the 15 March terror attacks "have nothing to do with the technological capabilities of the agencies involved and all to do with either mistaken priorities, scarce resources or an inability to follow up on leads," Dr Buchanan said.
He said Project Speargun - a metadata probe on the southern cross cable - would not have helped prevent the attack because it was directed at foreign traffic coming into New Zealand.
And contrary to what has been said, the idea behind the project "never went away", but was "supplanted by newer technology" that was much more sophisticated.
"So there may be another name for it, but it never went away.
"And so for a fellow like Mr Bridges to be sitting on the intelligence and security and not know that strikes me as a little bit odd."
Dr Buchanan said New Zealand's spy tech was "pretty much state of the art" and the failure to identify the person accused of the mosque attacks was a "[more] failure of human intelligence ... than it is the failure of any signals intelligence".
Public doesn't want 'knee-jeck' swerve into mass surveillance - Green Party
Green MP Golriz Ghahraman cautioned the government to wait for the findings of the Royal Commission before taking any drastic action.
The public would not stand for "knee-jerk" mass surveillance suddenly being introduced, she said.
"New Zealanders have shown us over the past week that they are united in love for the Muslim community and a resolve to protect our minority communities.
"But we want to do that, as we've always done that, within a human rights framework. That's who New Zealand is. We're not America - and our reaction to this has shown that."