The Law Society says the defence of provocation should be kept until something better is developed to replace it.
But gay rights advocates say the defence has legalised gay bashing and should have been ditched years ago.
Parliament's justice and electoral select committee is considering a government bill to abolish the partial defence of provocation.
Justice Minister Simon Power said earlier that the change was on the cards before the controversial case of Otago University tutor Clayton Weatherston, who argued he was provoked into stabbing former girlfriend Sophie Elliott 216 times.
Weatherston pleaded guilty to manslaughter but the jury found him guilty of murder.
The Law Commission has twice recommended abolition, in 2001 and in 2007.
In a written submission on the bill, Law Society president John Marshall, QC, said the commission's previous recommendation was made when the Labour Government was planning to introduce a Sentencing Council and sentencing guidelines, but they were no longer going ahead.
The society's criminal law committee believed the defence should be retained "pending the development of other forms of defence".
Among its concerns were that it was not always appropriate that a provoked killer be labelled a murderer and that it should not just be up to a judge to determine where there was enough provocation to reduce the charge to manslaughter. It also said sentencing might not take into account lesser culpability.
"If the partial defence were to be abolished, juries might convict on the alternative charge of manslaughter based on their sympathy for the defendant rather than on rational grounds," the Law Society said.
Mr Marshall said forms of defence could include, for example, diminished responsibility or degrees of murder.
Tony Simpson of the gay rights group Rainbow Wellington was keen to see the defence dropped immediately. He said the defence, while seldom successful, had been used to assassinate the character of gay victims and it was hard to accept when it resulted in an offender escaping a penalty.
In July, Hungarian tourist Ferdinand Ambach was found guilty of manslaughter rather than murder after killing 69-year-old gay man Ronald Brown in Onehunga.
Mr Brown was beaten with a banjo before its neck was rammed down his throat.
It was alleged he made sexual advances to Mr Brown.
Mr Simpson said there had been calls for change since Charles Aberhart, a gay man from Blenheim, was kicked to death in Hagley Park in 1964 by six youths aged 15 to 17.
Despite evidence they had gone to the park for a "spot of queer-bashing", they were found not guilty after alleging that Mr Aberhart had provoked them by making a sexual advance.
Mr Simpson said it appeared the Government was willing to act when the defence was unsuccessful in a case involving a man and a woman, despite years of agitation for change after it was successfully used in cases against gay victims.
The existing law was a "homophobic hangover", he said.
Kiri Hannifin from the National Collective of Independent Women's Refuges said her organisation supported the repeal.
"The law has done nothing to protect victims of violence. Indeed, perversely it's often used against them."
However, she was concerned the law did not properly cater for victims of domestic violence who killed their abusive partners.
"We're concerned that if provocation is abolished and sentencing isn't appropriately addressed, there is a huge gap in our legal framework for women who kill their partners because they believe that if they don't, they or their children will be killed."