National's candidate for Maungakiekie, Greg Fleming, compared civil unions to polygamy and incest during the civil unions debate.
But on Tuesday he admitted his comments "weren't helpful" and "I wouldn't make them again".
At the time, Fleming was the managing director of the Maxim Institute.
He penned a press release at the time calling into question the Government's motives behind introducing the Civil Unions Bill.
The Civil Unions Act was passed in 2004 - it preceded our same sex marriage laws.
The Act allows for couples who are unable to be married - like same sex couples at the time - to legally register their relationship.
"We must be clear that the sole purpose of this Bill is to provide for same-sex marriage in all but name. Government propaganda suggesting civil unions are an alternative for defacto couples is just a farce," Fleming wrote in a press release.
In the press release, he said the Government is discriminating against those in polygamous or incestuous relationships.
"Why is the government allowing discrimination to continue by refusing to legally recognise other relationship forms such as the union of siblings or more than two people?"
In a statement to Newshub after the initial publication of this story, Fleming said twenty years on, "I very much support civil unions".
"My comments two decades ago were trying to make a point about contractual law but weren’t helpful and I wouldn't make them again," he said.
"Our marriage laws are now well and truly settled and I support leaving them as they are."
Speaking to media on Tuesday morning, National leader Christopher Luxon said they weren't his views.
"They are obviously comments from 20 years ago, they are comments I absolutely utterly reject. I am a big supporter of same-sex marriage. People should be free to love whoever they want to love," Luxon said.
"I am very pleased with the progress we've made on selection processes... We've actually been able to get a whole bunch of people from a very diverse set of backgrounds. It's a broad party. We have people with a range of views."
Luxon said he was very supportive of the Civil Unions Bill.
"I have always been very supportive of same-sex marriage," he said.
Fleming was announced as National's candidate for Maungakiekie last month, saying he had lived in the community for 25 years.
He was a founding chair and trustee of Te Whakaora Tangata, a Manurewa-based charitable trust focused on addressing intergenerational poverty.
He co-founded the Maxim Institute and the Venn Foundation, an educational institution. He was the chief executive of The Parenting Place between 2015 and 2020.
"I've spent my career delivering for people who've trusted me to do a job," he said.
"I'll be fighting hard to earn the opportunity to do the same for the people of Maungakiekie as part of the National team. It's where my wife and I raised our five kids and it's where I'll be spending every day meeting as many people as I can in the run up to October 14."
Newshub has contacted the National Party to get a comment from Fleming.
