Despite a parliamentary committee recommending the partial defence of provocation should be abolished the Law Society wants it to stay.
The justice select committee yesterday recommended the opportunity for a defendant to get a murder charge reduced to manslaughter because they were provoked should be removed from statute and common law.
The MPs recommended the Crimes (Provocation Repeal) Amendment Bill should be passed into law.
Jonathan Krebs, convener of the society's criminal law subcommittee, today said some form of diminished responsibility was needed.
Select committee chairman National MP Chester Borrows said diminished responsibility was catered for in sentencing.
The jury must consider whether murder was committed and the judge should consider provocation in the handing down of a sentence, he told Radio New Zealand.
The committee's report said allowing judges to consider provocation as a mitigating factor in sentencing would mean in extreme cases someone found guilty of murder could get less than life imprisonment if the judge believed that sentence was "manifestly unjust".
The partial defence of provocation came under intense debate after Otago University tutor Clayton Weatherston argued he was provoked into stabbing girlfriend Sophie Elliott 216 times.
Weatherston pleaded guilty to manslaughter but the jury found him guilty of murder.
In July, Ferdinand Ambach was found guilty of manslaughter rather murder after killing 69-year-old gay man Ronald Brown.
Mr Brown was beaten with a banjo before the instrument's neck was rammed down his throat. It was alleged Mr Brown made sexual advances to Ambach.
Ambach and Weatherston last week both mounted appeals.
NZPA