Key Points:

Law Commissioner Sir Geoffrey Palmer says the time could be right to re-examine the right of people accused of crimes to remain silent in the face of police questioning.

His suggestion comes amid mounting anger that the killer or killers of twin babies Chris and Cru Kahui may never be brought to justice.

In the early days of the investigation into the deaths, police were hampered when the twins' family refused to talk to them.

The twins' father, Chris Kahui, was found not guilty this week, and police say no one else will face charges related to the killings.

Napier Labour MP and former criminal defence lawyer Russell Fairbrother yesterday called for a review of the right to silence of criminal suspects or those charged with a criminal offence.

He did not know whether Mr Kahui was "truly innocent", or had received the benefit of the doubt in a case rife with uncertainties.

"But I do know that someone in that house truly knows what happened. It cannot be right that a guilty person is avoiding criminal sanction for this most heinous of crimes."

Mr Fairbrother said he would discuss the matter with the Minister of Justice, Annette King, with a view to introducing a private member's bill.

Sir Geoffrey, a former Labour Prime Minister, said talking about the law, and possible changes to it, was a good discussion to have - although any changes would take time.

He said changes to the law had been considered "from time to time".

"It is not a change that would happen quickly, but talking about it is not wrong."

But the right to silence was deeply embedded in New Zealand law.

"Changing it is a very big operation. There are arguments on both sides - no question."

Mr Fairbrother said New Zealand today was different from old English society, which developed the law to protect powerless suspects "against the overwhelming power of the state".

New Zealand's human rights-centred law had created many rights which did not exist less than a century ago.

But Law Society spokesman Jonathan Krebs, who is also convener of the society's criminal law committee, said changing the "cornerstone" law was an unnecessary reaction to what had been a very difficult case.

It was a known trend that changing common law in response to a hard case often resulted in bad law, he said.

"And I'm reasonably confident the Law Society would represent a very conservative view. I don't think it's a topic that needs discussion."

Auckland University associate professor of law Scott Optican said calling for a review was ridiculous.

Although police could not force people to speak before a trial, they could call them as witnesses in court, where they had to speak.
National Party justice spokesman Simon Power said he would look at any proposal tabled in Parliament.

"It is fair to say some issues have arisen in the last few days that would warrant a further focus."

A spokesman for Ms King said the minister would make no comment on Mr Fairbrother's proposals.