Bid to change provocation law in NSW

People who kill their partners in fits of jealousy won't be able to use the legal defence of provocation, under new laws before NSW parliament.

Christian Democrat Fred Nile introduced the government's legislation, which will target the use of the partial provocation defence in murder cases, in the state's upper house on Wednesday.

The law will only allow cases of "extreme provocation", where a serious indictable offence has been committed, to be used as a partial defence.

The measures are a response to Sydney man Chamanjot Singh being given a six-year jail term after he was found guilty of manslaughter, rather than murder, for attacking his wife, Manpreet Kaur, and cutting her throat eight times.

The jury accepted he had been provoked by his wife's threats she would have him deported and that she loved another man.

Mr Nile said the measures will put restrictions on the partial defence of provocation, while retaining the defence in cases involving long-term domestic violence.

He told the chamber on Wednesday the laws will make sentences, such as the one handed to Singh, "a thing of the past".

Attorney-General Greg Smith says the bill does away with a law that was seen by some as being biased against women, by blaming the victim's behaviour for the offender's loss of self-control.

"Importantly, an accused can no longer use this excuse because their partner was unfaithful or wishes to end the relationship," he said.