Internal Affairs Minister Tracey Martin says she is "extremely disappointed" in her coalition partners for blocking her plans to restrict access to online pornography.
The New Zealand First MP said she failed to get agreement from the Labour and Green parties to advance a proposal which would have introduced pornography filters on home internet connections.
She accused Labour of not supporting the proposal because it was concerned about being portrayed as "nanny state" in election year.
Labour said it was not completely against the idea, but that it needed more work.
Martin, who is also Children's Minister, drafted a Cabinet paper with measures to prevent children and young people from viewing pornography online.
It would have required internet service providers (ISPs) to install porn-blocking software with all new internet connections, forcing subscribers to "opt out" of the blocking software rather than actively "opting in" to it.
She wanted legislation to be introduced to Parliament this term.
"It's not going anywhere," she told the Herald. "I couldn't get cross-party support."
Martin did not hold back in her criticism of her coalition partners.
"Labour had a political aversion to doing something that they considered might be nanny state for them," she said.
"The Greens came back and said, 'We believe there are times when it is appropriate for children to see naked people in a consensual relationship' - which is not what we're actually talking about.
"And I think there's a conversation to be had about whether that's appropriate for 5-year-olds as well."
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Labour and the Greens both said they did not disagree with the goal of keeping children safe online. But they both raised concerns about whether an internet filter would actually work.
"There is no disagreement on the outcome the Minister is trying to achieve," a Labour spokesperson said.
"Questions around the filter's effectiveness and how it might be implemented were raised as part of usual coalition consultations.
"It was anticipated that further policy work would continue to address the issues raised."
A Green Party spokesperson raised similar concerns.
"There remain valid questions around whether filters can be precise enough to capture restricted content without taking down or censoring other content too.
"International evidence shows that filters are easy to circumvent while often over-blocking, limiting access to those seeking information about sexual health, relationships, or identity."
The Greens wanted to improve controls for content which already met the standard of objectionable under existing laws - though the party recognised that not all sexually explicit material met this standard.
The anti-pornography proposals were based on a British law change, but the UK Government scrapped that plan in 2017 in favour of broader laws addressing extremism.
The New Zealand proposals were opposed by Internet NZ, which said the blocking software would be costly, ineffective, provide a false sense of security, and was an unjustified government intervention. Households should be able to choose their own filtering software, which was widely available, the lobby group said.
Martin conceded that porn blocking measures would only be partly effective because they did not cover mobile phones. But she had made protecting children from pornography a priority and wanted a range of measures, including regulation, to address it.
The minister's work was partly influenced by five bills proposed by conservative lobby group Family First. The organisation's national director Bob McCoskrie said he was "gutted" Martin's work could not proceed.
"We think the protection of young people from the proliferation of porn and the nastiness of porn available now is far greater than the so-called protection of the industry or not wanting to ruffle feathers. Parents are crying out for help.
"These proposals weren't banning pornography, they were a middle ground, an opt-in rather than an opt-out. It was a pretty reasonable approach."
Research by the office of Chief Censor David Shanks in 2018 found that 75 per cent of New Zealand boys and 58 per cent of girls aged 14 to 17 had seen porn online, either deliberately or by accident.
About 69 per cent of teens who saw porn at least once a month had seen "violence or aggression", and almost half of teens who had had sexual relationships said they had "tried doing something [they] saw in porn".
Martin is still progressing another piece of legislation which targets extremist content online and requires social media companies to be responsible for content they host in New Zealand.