Hayes said that between 2002 and 2011 there were 798 young brides in New Zealand, 388 of whom married overseas. About 80 16- and 17-year-olds marry a year.
"We know that some girls also are exported to New Zealand for the purposes of forced marriage. All this has to do with a fee to parents, a bit of a story given to the young woman who is told, 'you come over here, you'll get free education, we'll look after you'.
"And they end up as slaves in an unwanted marriage and one that ends in violence, to the point that we hear stories of where young women lose their lives, and there is no justice for them."
Labour MP Poto Williams said Labour supported the legislation, which will allow cultural practice to continue but add an "element of safety".
Green Party MP Jan Logie said forced marriage was a form of slavery.
"We have heard from advocates in Shakti [women's refuge] who have been in touch with some of these young women who have been forced into these lives of slavery and because of the way our laws exist at the moment really have very, very little protection," Logie said.
"This is a great bill. It is about time. We need to make a stand as a country against the exploitation of women and girls."
New Zealand First MP Tracey Martin said the legislation should not just cover young people brought to New Zealand to get married.
"I know intimately young women who have actually been sent back to Iraq at the age of 15, were married and produced two children, and were brought back to New Zealand. They brought that husband with them, who was some years older than them. They did so against their will, but their parents took them there."