Key Points:

The National Government's plans to give the police unfettered power to take DNA from those they arrest has concerned its own Attorney-General, Chris Finlayson, who said it appears to breach the Bill of Rights.

A report by Mr Finlayson said the DNA plan "appears to be inconsistent" with the right against unreasonable search and seizure under the Bill of Rights.

National's plan would give police the power to take DNA from those they "intend to charge" with an imprisonable offence without the safeguard of judicial or other independent approval.

Mr Finlayson said such safeguards were required in jurisdictions that used a comparable DNA scheme, including New South Wales, Victoria, Canada, the United States, Germany, Japan and the Netherlands.

Mr Finlayson said the only comparable schemes were in the South Australia, Tasmania and the United Kingdom - noting that in the United Kingdom, the lack of safeguards is currently under review after it was found to breach the European Convention on Human Rights.

Mr Finlayson said he could not see any special circumstances in New Zealand to justify not having statutory safeguards.

Mr Finlayson's report was completed as part of the Attorney-General's "vetting role" of legislation that may breach the Bill of Rights. It is essentially his opinion as the Government's lawyer, and in his capacity as an MP he will almost certainly still vote for the bill.

Currently, DNA samples can only be taken from certain convicted offenders.

Prime Minister John Key yesterday said the Government was expanding the criteria because DNA was the "modern-day fingerprint".

But Mr Finlayson's report notes this similarity "is not generally accepted". Mr Finlayson's report quoted a recent finding of the Supreme Court of Canada, later cited by the European Court of Human rights that: "Unlike a fingerprint [DNA] is capable of revealing the most intimate details of a person's biological make-up ... The taking and retention of a DNA sample is not a trivial matter and, absent a compelling public interest, would inherently constitute a grave intrusion on the subject's right to personal and informational privacy."

Mr Finlayson's report noted the bill allowed police to take samples, where necessary with "reasonable force", whether or not Police have any reason to suspect [the] charged person with previous offending ..."

Mr Finlayson noted the bill "will undoubtedly result in increased rates of identification and prosecution of offenders". It also provided controls over how long samples were retained and restricted unauthorised use.

The Criminal Investigation (Bodily Samples) Amendment Bill was to have its first reading in Parliament last night. National plans to phase the DNA plan in, with the new powers initially applying only to a list of relevant offences ranging from murder, rape, burglary and peeping in July 2010, then to all imprisonable offences from October to December 2011.

National also introduced its Gangs and Organised Crime Bill last night, broadening the criteria under which police can bug conversations, clarifying the charge of participating in an organised criminal group and doubling the maximum sentence for this offence from five to 10 years.

What the New Zealand Bill of Rights says: "Everyone has the right to be secure against unreasonable search and seizure."

What National says its DNA bill will do: "Allow Police (without prior judicial approval) to collect DNA from a person they intend to charge with an offence."