MPs have heard the defence of provocation in court cases is a "homophobic hangover" that should long have been done away with.
Parliament's Justice and Electoral Select Committee is hearing submissions on a bill that will repeal the partial defence.
Calls for the removal of the defence were renewed following the trial of former Otago University tutor Clayton Weatherston, who unsuccessfully tried to argue he was provoked when he killed his ex-girlfriend Sophie Elliott.
Around the same time, the defence was successfully used by Ferdinand Ambach, who killed a gay Auckland man, Ronald Brown, claiming Mr Brown had made unwanted sexual advances to him.
A Radio New Zealand political reporter says the defence, when used in that situation, has been coined the "homosexual panic" defence.
The Rainbow Wellington group says the existence of the defence is a signal that violent killing of a gay man is of less consequence than the killing of another.
Chair Tony Simpson told MPs on Thursday it is ironic that in numerous cases where the defence was used successfully when it should not have been, agitation for its repeal was ignored.
He said the defence has too often been used to mask community prejudice.
The committee is continuing to hear submissions.