Hundreds of protesters marched on New Zealand's Parliament Wednesday, demanding lawmakers throw out a proposed new law that critics say removes parents' right to smack their children.

About 500 people, some pushing children in strollers, carried banners reading: "Don't mess with the family" and "Kids don't belong to the state" as they rallied in the largest of several protests against the bill in recent days.

Parents, some churches and political groups are trying to derail a plan to repeal a section of New Zealand's Crimes Act that allows parents to use "reasonable force" to discipline their children.

Supporters of the amendment say the current law has been used to secure acquittals for parents accused of beating their children with everything from lumps of lumber to electrical cables.

As the protest group sang the national anthem in front of Parliament, about 50 counter-protesters chanted "2,4,6,8 — teach your children not to hate."

Police stood ready to separate the two sides, but there was no trouble.

Protest organizer Lindsay Perigo told the crowd the changes were backed by a small minority only.

"The nanny state has well and truly overstepped the mark," he said, as the crowd waved banners reading: "A smack is not a beating," "Let parents be parents" and "Down with Nanny state."

"Just because you oppose the bill doesn't mean you support smacking," Perigo told The Associated Press. "But you support the parents' right to make the decision."

Lawmakers were due to debate another stage of the so-called anti-smacking bill's passage toward law on Wednesday.

According to its promoter, Green Party lawmaker Sue Bradford, the change does not outlaw smacking. Instead, the bill aims to prevent alleged abusers from using the "reasonable force" argument as a defense, she said.

Angela Wolff, a mother who took part in Wednesday's protest, said the change would impair her ability to control her 1-year-old daughter, Lara.

"You can't just lump parents in with (child) abusers. The bulk of parents won't be abusers. A smack is a smack and an assault is an assault," she said, adding that the law should be clarified to better define force.