Offending against police or prison officers - from assault to theft to sexual crimes - could see longer sentences than other offending, if the Government passes legislation it plans to introduce next month.

Yesterday, Justice Minister Simon Power said he had Cabinet approval to introduce legislation to make judges consider a harsher sentence if the victim was a police or corrections officers.

"Under the current law, the fact that an offence has been committed against a law enforcement officer is not an aggravating factor that must be taken into account at sentencing, and the Government wants to change that," Mr Power said.

"We want to ensure this is taken into account by judges when sentencing offenders. At present it is not a mandatory consideration."

But Jonathan Krebs, convenor of the New Zealand Law Society's criminal law subcommittee, said judges already took aggravating factors into account.

"I would question whether such a prescriptive change is really necessary. But we endorse any changes needed to make sure offences against prison officers are regarded with the same seriousness as those against police."

There are already offences in the Crimes Act that specifically relate to assaults on a constable, which carries three times the maximum jail-term for common assault. But this proposal relates to sentencing rather than criminal offences.

There have been several high profile assaults on police officers this year, including a constable being left in a coma after being attacked by a mob of teenagers.

Between the 2004-05 year and 2008-09 total assaults on police increased by a third, from 1869 to 2481, while serious assaults increased 38 per cent, from 298 to 412.

Between 2004-05 and 2008-09, the total number of assaults on Corrections staff increased from 151 to 304. In May, Jason Palmer was the first prison guard to be killed in the line of duty after he was punched at Waikato's Spring Hill Prison.

Minister of Police and Corrections Judith Collins said an attack on a police or Corrections officer was "an attack on the community and the rule of law".

Meanwhile, the Ministry of Justice is looking at the law around assaults on law enforcement officers and will report back to the Government next June.

Current offences include a maximum of 14 years' imprisonment for using a firearm against any police, traffic, or prison officer, and a maximum sentence of three years for aggravated assault on a constable on duty.

1869 assaults on police between 2004-2005

2481 assaults on police between 2008-2009

151 assaults on corrections staff between 2004-2005

304 assaults on corrections staff between 2008-2009