Minister of Justice Andrew Little had a fiery debate on Magic Talk on Wednesday about New Zealand's 'right to silence' laws.

Sean Plunket invited the minister onto his show after Little spoke to Ryan Bridge on Tuesday, where the pair had an on-air clash about the same subject.

Little's appearance came in the wake of a brutal assault on a young boy in the Hawke's Bay who will be left with severe brain damage. The boy's family haven't released any information and continue to remain tight-lipped to police.

This has led to calls from both the Opposition and Children's Commissioner Andrew Becroft to abolish or amend the right to silence.

Little says the changes the National Party want to make would reflect a 2014 law in Victoria, Australia, where failure to disclose that a child is being abused is against the law.

For his interview with Bridge, Little incorrectly received advice relating to a 2005 law from Victoria which requires compulsory reporting if someone suspects a child is being abused.

Plunket says since there was confusion in Tuesday's interview, he wanted to give Little another opportunity to clarify why he won't adopt the National Party's law. 

Plunket began the debate by citing law that says government departments such as Fisheries, Inland Revenue and the Serious Fraud Office can question people who they believe have broken the law - there is no right to silence.

This led to the beginning of their fiery on-air argument.

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"Sean, Sean, let's be fair, you've got me on the programme, let's behave ourselves," Little says.

He explains that the laws Plunket has mentioned involve situations where there is a reason of suspicion that someone is an offender.

"Andrew, could I just put it to you. You've put that view, here's my view," Plunket says.

"When a kid's lying in hospital brain damaged, with damage to almost every part of his body, I'm going to make a reasonable assumption that a crime has been committed."

This led Little to say that radio hosts like to "whip it up" when talking about a controversial topic.

"Oh crap, don't pull that on me, Minister. Do not use my profession as an excuse for your lack of humanity," Plunket says.

Little responds that he understands "that's what happens in radio land", but as Minister of Justice he has to find a balance between catching offenders as well as ensuring the system doesn't allow abuse of power towards innocent people.

He says he's no different to any other New Zealander because he wants to see the person who "brutalised" the young boy brought to justice.

This led Little to say that radio hosts like to "whip it up" when talking about a controversial topic.

Once again, this led to a fiery escalation between the pair.

"You can actually do something about it, but you don't seem willing to," Plunket says.

"You're not doing a bloody thing, Minister.

"I now form the view, I'm sorry, listening to you that you simply do not give a shit."

Little says he has another job to do, which is to make sure there's a system that works to get the perpetrators. He was cut off by Plunket before he could finish his sentence.

"I have found this conversation one of the most disappointing with any serving minister in my life," Plunket says.

"The fact that you have made it personal and thrown personal insults about a matter this is so grossly disturbing to so many New Zealanders is incredibly disappointing."

Little's phone connection is then cut.

Plunket says later in his programme that he wanted to invite Little on to have "meaningful dialogue" about the type of law change that the Opposition was proposing.