People who witness child abuse but refuse to speak to police should face three years in jail, National leader Simon Bridges says.
But Justice Minister Andrew Little considers this a step too far for those who exercise their right to silence, and is instead looking at other restrictions on suspects who stay silent at the time of arrest.
The case of the severely-beaten 4-year-old in Flaxmere has prompted Children's Commissioner Andrew Becroft and the Act Party to question the right to silence. Extended family members of the boy who were at the home when the abuse took place continue to stonewall police.
This morning Bridges added his voice, saying that a National Government would introduce a new offence for failing to give police information in child abuse cases.
It would carry a maximum penalty of three years' jail.
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"If someone was to see the abuse ... they would have an obligation to do something," Bridges said.
"There would though be a reasonable excuse defence around, for example, being fearful for themselves."
The new offence would be different to the proposal in National MP Chris Penk's member's bill, which would enable a judge to draw a negative inference from a defendant who refused to give evidence.
But Little was dismissive of Bridges' proposal.
"I want to know whether this will add anything or whether it's just populist talk."
Little said compelling people to talk to police was a "fraught issue", as it could end up harming innocent people.
The right to silence was a fundamental human right and should not be changed without rigorous public debate, he said.
"What powers do you want the police to have, bearing in mind that those powers will be used in any other occasion, including in relation to people who might not have harmed anyone but were in close proximity?"
Little has asked Justice Ministry officials to look at the British system of police cautions at the time of arrest.
"This is along the lines of, 'You have the right to remain silent but you may harm your defence if you fail to say anything you later rely on in court.'
"I think this approach offers a better balance between the right to silence and the ability to be properly held to account in court."
Prime Minister Jacinda Ardern has urged the family in the case of the 4-year-old to come forward.
She supported Little looking at police cautions.
"I don't think anyone is comfortable [with] what's happened in this case, when no one is being help responsible for the harm to a vulnerable child, so we're looking into it."
She said changes under the previous National-led government did not appear to have worked.
National had introduced a new offence in 2011 of failing to protect a child or vulnerable adult; so far 34 charges have been laid against 25 people.