Support for the new child discipline law introduced last year is put at just under half in a survey by the Children's Commission.
The poll was commissioned to create a benchmark for further monitoring of the law passed, which removes the defence of using "reasonable force" to correct a child.
The commission wants to gauge people's opinion and understanding of the law, and hopes similar surveys will run every three to five years.
Forty-three percent of respondents to the independent survey support the law, while 28% opposed it.
The research found 58% still believe there are times when physical punishment is acceptable.
Children's Commissioner Cindy Kiro says that figure is down from 87% when a similar question was asked in a survey 15 years ago.
The survey found men are more likely to be supportive of physical discipline and opposed to the law change.
Green Party MP Sue Bradford, who initiated the law change, says the male trend is not a surprise.
"Some of the people who are so keen to maintain their legal right to physically discipline their children are those who often see their children as their property, just as men used to, and in some cases still do see women as their property, or their wives as their property.
"That's where a lot of this old law came from - the idea that wives, children and servants were property and, therefore, could be subject to physical discipline."
Family First says the poll is completely inconsistent with others done since the law change.
Larry Baldock, the campaigner who organised a petition against the law, initiating a referendum, says the results contradict what he was hearing from people while collecting signatures.
"The most accurate survey is going to be a referendum, where everyone gets a chance to answer the question: 'Should a smack as part of good parental correction be a criminal offence?' That's what the petition I completed is to secure, and I just say let's let it be settled."
The referendum will be held in August 2009.