ACT Party leader David Seymour and leader of the opposition Simon Bridges are urging caution on Justice Minister Andrew Little's proposal to make hate crimes a new legal offence.
Mr Little said the current law on hate speech was not thorough and strong enough and needed to change.
He said the Christchurch shootings highlighted the need for a better mechanism to deal with incidents of hate speech and other hateful deeds.
He has asked justice officials to look at the laws and he was also fast-tracking a scheduled Human Rights Act review.
"The conclusion I've drawn as the minister is that the laws are inadequate and I think we need to do better," Mr Little said.
Watch: David Seymour in the Auckland studio
However, Mr Seymour told Morning Report it would be divisive if it meant certain people were deemed more deserving of legal protection than others.
He said that similar laws in Britain had gone so far that the government was considering adding men and women to protected groups that could be subject to hate crimes.
"You end up creating a lot of resentment that descends into farce and where you arrive is where we should be anyway - where all people have commune humanity and inherent dignity.
"It's divisive to start singling out and saying this person should be subject to a crime and this person shouldn't be.
Mr Bridges was taking a wait-and-see approach and said the review was the right thing to do, but government must be cautious about how it was treading.
"I have no criticism of Little having a review of this, but where free speech line crosses into hateful incitement of violence is not easy. Let's see the review, let's look at it carefully, and let's have that conversation," he said.
Mr Bridges said freedom of speech was a bedrock principle of New Zealand society and sometimes we have to tolerate views that we disagree with, or even find offensive within that freedom.
"Where the line on these things is so incredibly hard," Mr Bridges said.
"We need to take our time and do it right."
The former race relations commissioner Joris De Bres told Morning Report he repeatedly asked the government to create a central system for recording hate crimes, but was told it wasn't necessary.
Mr De Bres said if issues were dealt with in the place they happened, for instance social media and workplaces taking action against racist or homophobic comments, it would be a good start.
But, he said, the worst of these crimes are committed in the streets, with swastikas painted on Jewish headstones and mosques being descrated.
"What we have to do is look at it now with the commitment we have to the safety of New Zealanders, and in particular right now, the commitment we have to the safety of Muslim communities.
"We know, from what they say to us, and we've known for a long time that they are abused on the street, they are harrassed at the supermarket carpack, they are assaulted and their mosques and even their homes are damaged."
Mr De Bres said racism, or white supremacism, was a cause behind the crimes, and it needed to be dealt with.