A criminal law professor says he doubts whether the latest change to the Sentencing Act will have much of an impact on how criminals are sentenced.
Green MP Keith Locke also questions whether it will make any difference.
The Government says it will introduce legislation next month to make assaulting a law enforcement officer an aggravating factor to be considered by judges at sentencing.
Kevin Dawkins of Otago University says courts have commonly regarded assaults on police officers or other law enforcement officers as an aggravating circumstance.
He believes the amendment simply formalises how such cases have been dealt with in the past.
Mr Locke says that the Government is right to do what it can to discourage attacks on police and Corrections officers, and that as long as there is no formal requirement to make longer sentences a requirement he will support the move.
Assaults on officers rose by a third
The Government decided on the amendment because the number of assaults on police officers rose by a third - to 2481 - between 2004 and 2009. Serious assaults increased 38% to 412.
Over the same time, the number of assaults on Corrections officers that required hospitalisation or time off work doubled from 151 to 304.
Acknowledges that the move won't automatically mean longer sentences, Police Minister Judith Collins says it's still more effective than increasing the maximum penalty for the existing special offences for attacking a law enforcement officer.
It also sends a strong signal that the Government will do everything it can to protect officers on the job, she says.