Describing it as a "bad time" in her life after experiencing a miscarriage, Quinn said:
"It was a horrible mistake I made and one I regret it very much."
New Conservative leader Leighton Baker is standing by Quinn, said she had disclosed the offence.
A report published in the Southland Times in 2000 revealed the then-36-year old student was sentenced to six months' periodic detention after lying in an affidavit, forging an obstetric discharge record and giving a forged letter to her lawyer as evidence a baby had been born.
She had miscarried early in a pregnancy but after the relationship with her partner soured she determined to carry on with the charade forging a letter from Southern Health showing she had given birth, and even taking photographs of another baby to support her lies.
Judge Phil Moran described the fraud case as involving a set of "bizarre circumstances".
"Such was your bitterness at his breaking the relationship that after you miscarried you were determined to carry on with the pretence that you in fact carried a baby to full-term and gave birth," said the judge.
"You went so far as to seek paternity and custody orders to make an application to the Family Court supported by an affidavit in which you told lies. This is committing a crime of perjury."
The judge said not only had she lied on oath but had been involved in creating documentary evidence to support her lie.
The charges had struck at the very administration of justice, he said in sentencing.
Today Quinn said it was traumatic period in her life but one she couldn't change.
She always knew it was something that could resurface at any time, but had been upfront about the conviction with her party leadership.
"It was something that I don't deny," said Quinn.
"I knew it was there and I declared it from the get-go to the party.
"And yes, I did know it could possibly rear its head."
She tearfully added there was "a lot of history involved around what I did".
"I completely appreciate that it was something from my past and I can't change that."
It represented a dark time with her mental health but Quinn hoped this might possibly represent a chance to focus on an issue that affected so many women.
"I really hope that there can be more funding for mental issues," she said. "And I really hope that nobody ever has to go through the trauma I went through when I lost a child. That's the catalyst why I did it."
Baker today stood behind his Taupō candidate, saying Quinn had declared the conviction when she put herself forward.
While admitting he didn't know anything about the case's details to highlight an incident from 20 years ago sounded like muckracking.
"We want people to stand up - and good on them for having the courage to stand up - but it's shame when they're attacked for putting their heads above the parapet," he said.
"I have never met anyone who hasn't made a mistake.
"She did the crime. We don't have a problem with that.
"We are a party that believes if you commit the crime, then do your time, and then get on with making a positive contribution to society," said Baker.
"Quinn has certainly done that. There was no money involved in her mistake and no harm was done to anyone else. She did her six months' community service, and has contributed superbly to her community. She deserves a fair go."
He added it was not something she had continued to do and this revelation appeared to be motivated by someone with a vindictive agenda.
"To me it's a little bit of a witchhunt to trawl through someone's past and bring up something from 20 years ago."
An Electoral Commission spokesperson said to be eligible to be a candidate, you must be New Zealand citizen and enrolled to vote. A previous conviction did not disqualify you from standing.
According to her online biography, Quinn was an adopted child who was born in Invercargill and attended Central Southland College in Winton.
She lived in Invercargill for a large part of her adult years, then spent 12 years in Christchurch, eventually moving to Taupō in 2012.
The online biography outlines her business background saying she has owned several hairdressing businesses in a 42-year career in the industry.
The grandmother of five also outlines her work with the Children at Risk and Education (CARE) hapori initiative as a facilitator and advocate, providing awareness, education and prevention help in connection with the areas of child abuse, neglect and poverty.
