The social agency, Barnados, is renewing calls for a cross-parliamentary approach to child abuse.
The Sentencing (Offences against Children) Amendment Bill was passed unanimously by Parliament on Saturday under urgency.
The bill makes offending against a child a specific aggravating factor during sentencing, when violence or neglect is involved.
But Labour has said the changes won't make a difference to child neglect.
That's prompted the chief executive of Barnados, Murray Edridge, to call for parliamentarians to put aside their politics.
He says children are too important to be caught up in political point scoring.
Mr Edridge says what's needed is MPs who are committed to outcomes for children, to valuing children and to giving children the right start in life, which they deserve and which society will benefit from.
The Government says it's important the changes have been made before Christmas, when many children are especially vulnerable to abuse and neglect.
Mr Edridge agrees Christmas is a time of year when agencies see an increase in the level of child abuse.
He says the sentencing changes won't make an immediate difference, but are a good start.
Children's Commissioner Dr Cindy Kiro also says anything that signals child abusers will pay a heavy price for their crime is a good thing. But she does not think longer sentences will stop child abuse.
Justice Minister Simon Power said the changes will be a step towards making children safer.
