The Law Society has trashed the "three strike" sentencing bill, saying if Parliament wants courts to hand out tougher sentences it should broaden preventive detention laws.
The bill proposes to hand down a near-compulsory 25-year non-parole sentence for the worst criminals after their third serious offence.
Law Society spokesman Jonathan Krebs told Parliament's law and order select committee today that it was best to leave the discretion in the hands of the judiciary.
He pointed to studies that said serious crime increased under similar laws.
This was because an offender with two serious sentences had nothing to lose from killing witnesses when committing a serious offence.
Mr Krebs said the bill was a "blunt instrument" which would be counter productive and create unintended consequences.
The decision about the length of sentence a person received would effectively be taken out of the hands of judges and given to police officers, who decided what offence a person was charged.
Depending on which charge was laid, a person could get two to three years in prison or 25 years.
This would increase the incentive of offenders taking up the option of a judicial review of the charging police officer's decision.
This would place more pressure on the court system as would the fact that there would be fewer guilty pleas.
Mr Krebs argued that the extension of preventive detention sentencing in 2002 had been effective in handing out longer prison sentences for both one-off serious offences and repeat offenders.
If Parliament wanted to hand out even more severe sentences, then it could be done through changing the thresholds for preventive decisions and adjusting parole options.
The bill's promoter, ACT MP David Garrett, said the bill did offer judges some discretion not to hand down a 25 year sentence for a third-time serious offender if it was "manifestly" unjust.
Mr Krebs believed showing a sentence was manifestly unjust was too high a bar.
The ACT Party bill was backed through its first reading in Parliament by National, while being opposed by Labour, the Greens and the Maori Party.
The Government is not committed to backing it into law.
Justice Minister Simon Power has expressed some scepticism about the proposal and says he expected the issues to be debated at the bill's select committee stage.
