Principal Youth Court Judge Andrew Becroft says legislation to raise the minimum age for an offender to be dealt with in adult courts would fulfil international obligations and bring New Zealand into line with other developed countries.
Legislation to raise the minimum age for an offender to be dealt with in adult courts from 17 to 18 is reportedly being drafted.
Social Development Minister Ruth Dyson has said the bill could change before introduction into Parliament.
Judge Becroft, through a spokesman, said that as a judge he could not comment on proposed legislation that had not even been introduced yet, but observed a law change was needed to meet United Nations' requirements.
"The United Nations Convention on the Rights of the Child is the most signed UN convention, with only two countries not having signed the convention - one being the United States and the other being Somalia," he said.
"As New Zealand has signed the convention, incorporating it into law would normalise our laws [to be in line with] similar jurisdictions."
Police Association president Greg O'Connor has slammed the move as "absolutely and utterly ludicrous".
"The age at which offenders are committing serious crime is dropping, not rising," he said.
The National Party said the proposal was "preposterous" and the Government should ditch it.
"What kind of government would allow 17-year-olds to escape responsibility for their criminal actions," said associate welfare spokeswoman Anne Tolley.
"In addition, the youth justice system will not be able to cope with an influx of older offenders without huge investment in new facilities."
Ms Tolley said a Ministry of Justice report had revealed that teenage violent crime increased by 39 per cent between 1995 and 2006.
"It beggars belief that the Labour Government is willing to put greater stress on the system as well as allow teenage criminals to abrogate their responsibilities for the sake of bringing New Zealand into line with a United Nations convention."
New Zealand First MP Ron Mark supported the association's position.
He has a private member's bill before Parliament seeking a lowering of the age at which children can be prosecuted from 14 to 12.
Judge Becroft has told the committee considering Mr Mark's bill that it was "abysmally drafted".
He said children could already be tried in adult courts. "There is a means now to convict and transfer all young offenders to the district court for sentence."