A new bill that would force people to reveal relevant evidence will leave citizens without protection and give the state total power, say civil libertarians.

The New Zealand Council for Civil Liberties has labelled the Search and Surveillance Bill - recommended by the Law Commission and tabled in Parliament on Thursday - a "chilling piece of legislation" that takes away a person's right to silence unless convicted of an offence.

But Justice Minister Simon Power said the reforms, which update statutes up to 50 years old, would help investigations into drug offences and organised crime.

He said the bill comprised a "complex statutory test" that did not just determine whether a person had "crucial information".

"It is a matter of how they got the information, that it is right for the type of investigation and that the information would be evidential material," Mr Power said in a written statement.

But Council of Civil Liberties chairman Michael Bott said New Zealand courts would become like the "Star Chamber" court of law in 17th Century England, where "silence often amounted to literal suicide".

"The rack or thumbscrew has been replaced by imprisonment, nevertheless this is still an example of the state using its coercive power to extract information from its citizens," he told the Weekend Herald yesterday.

Mr Bott said that under the bill, anyone who had committed trespass could be forced to provide evidence.

"The trigger for an examination order [legal order to provide evidence] in a "non-business" context is that an individual or a group of three or more is or has committed an offence punishable by imprisonment."

Given that trespass is punishable by three months' imprisonment, this would make campaigning peace groups - such as the anti-Springbok Tour group in the 1980s - subject to the clause, he said.

The new bill carries a maximum penalty of one year imprisonment, or a fine of up to $40,000 for a body corporate, for an interviewee who refuses to answer questions without a reasonable excuse, or provides false information.

Police Association president Greg O'Connor said the reforms gave witnesses the protection of being compelled by law to talk. He said people were often afraid to speak up because of what the alleged criminals might do to them.

He said police would not be able to force people to give evidence without a court order and rubbished suggestions evidence would be "packaged" or given "spin" for the benefit of the judge.

"Civil Libertarians would say that. They need to look at the rights of all New Zealanders, not just criminals, particularly victims of crime."

Mr O'Connor said the bill would help police clamp down on organised crime, particularly professionals in the business side. This might be accountants employed to legally channel proceeds of methamphetamine operations, he said.

Criminal Bar Association president Anthony Rogers had not read the bill but was concerned by "any encroachment on a person's right to refuse to be interviewed by the police".

* Introduction of "examination order" power, where people believed to have material information about offending can be forced to answer questions.
* Police able to detain people while scenes secured and searched.
* People in charge of computers/networks obliged to help in searches.
* Police able to stop and search vehicles without a warrant.