"I don't believe he can be rehabilitated until he admits what he did and why he did it," she said.
"You can't tell me a guy who has been in jail for 22 years is still medium–to-low risk."
A recent Parole Board report revealed Taylor had been "withdrawn from the prison computer room because of inappropriate use of the computers" and while he was on release to work at Spring Hill he was said to have engaged in "rule-breaking behaviour".
The board was also concerned about Taylor's continued denial of any sexual motivation for Rankin's murder.
In the board's latest decision Taylor said his reason for taking Nicola Rankin in his car was that "he wanted to find out what she knew about the offending he was on bail for. He was also concerned it would affect his position with the St John ambulance."
The board said it was "deeply troubled" by the evidence of sexual offending "accompanying Mr Taylor's murder of Ms Rankin".
Nicola's mother said she got "stressed" each time Taylor sought parole.
But she travelled from her home in Australia back to New Zealand when required in a bid to ensure he stayed behind bars.
"I only live nine months out of a year - the other three are pure hell," she said.
"It never gets easier. I found it really tough last year, I was a mess."
Rankin remains angry that Taylor's offending not only took the life of her daughter, but also denied her being a grandmother.
Nicola would have turned 40 this month.
"There is not a day I don't think of her," she said.
When Taylor sought release from prison in 2009 it came to light at the Parole Board hearing that he allegedly abducted and raped a 14-year-old girl before going on to kill Rankin.
The girl didn't press charges.
The killer rapist met Rankin when they were St John Youth cadets. He picked her up and forced the teenager to walk into the remote Riverhead Forest, 35km northwest of Auckland, and bludgeoned her with a spade.
Taylor had just been released on bail for an attack on Amanda Watt in April 1996, where he threatened her with a knife, tied her hands behind her back and raped her in his car.
Taylor drove Watt to Muriwai beach, where he tried to force her into the sand dunes. But, fearing for her life, Watt managed to persuade him to return to the city.