Law change gives people who are affected by crime more voice in court.
Victims will now be freer to express their raw feelings in court, though judges will still be called on to prevent impact statements from going too far.
A law change designed to improve victims' rights comes into force today and will widen the scope of what information can be included in impact statements read during sentencing.
Justice Minister Amy Adams said it would allow victims to make "raw, emotional" statements but the line would be drawn at threatening or abusive comments. A judge would still have the last word on what could be included in a statement, but victims now had clear parameters about what they could say.
The changes followed several high-profile cases in which a victim's family were frustrated with the limits they faced when speaking in court and the way their statements were handled.
Kevin McNeil, whose mother Lois Dear was murdered in Tokoroa in 2006, said the changes were a positive step.
At the sentencing for Ms Dear's killer, Whetu Te Hiko, Mr McNeil was deeply upset his impact statement was "censored" and "watered down".
The judge eventually relented and let him read it unchanged, but he said having his statement rewritten and softened added huge stress during an already difficult time.
"I wanted it in my own terms," he told the Weekend Herald. "I'm a truck-driver and I wanted it in layman's terms, not with words that I didn't understand added to it.
Gil Elliott, whose daughter Sophie was murdered in January 2008, was frustrated when his carefully prepared, highly personal statement was "grossly" altered at the last minute and prevented him from criticising her killer, Clayton Weatherston.
"The statements are given after [the person is convicted]. So you already know whether they are guilty of murder, yet you're not allowed to criticise them," he said.
"They've killed your child. And you're not allowed to say what a swine they are for doing that."
Mr Elliott had mixed feelings about the law change because he believed people would still be prevented from directly criticising the criminal. He was also disappointed an offender would still be able to observe a copy of the statement before it was read aloud.
Ms Adams said the new rules meant comments which were "a bit offensive" to the offender would not automatically be discarded.
There would be clear restrictions, in particular on any statements which were false, threatening, abusive, irrelevant, or referred to the judiciary, witnesses or separate offending.
Victims of serious offences (rape, serious assault) will get the automatic right to read their statements in court. Until now, judges could decide whether individuals could appear in court to say their piece.
Mr McNeil welcomed this development. He said judges were "like rugby refs" because their decisions were unpredictable, and the rule change would give victims greater certainty.
Victims will also be able to submit visual data, including photos and drawings, in part so children could say more about a crime's impact.