The Attorney General has warned Parliament of possible breaches of human rights in the proposed "three-strikes" sentencing legislation.
The concerns are included in a report on the Sentencing and Parole Reform Bill, which was recently sent to a select committee.
The bill would see anyone convicted for a third time for violent or sexual offences, sentenced to prison for life with a minimum non-parole period of 25 years.
Attorney-General Chris Finlayson says a sentencing regime as outlined in the bill, raises an apparent inconsistency with the Bill of Rights.
He says it may result in disparities between the treatment of offenders and gross disproportionality in sentencing.