Kannewischer was 85 when he was jailed for eight years.
He became eligible for parole in July but was refused an early release from prison.
Parole Board panel convenor Judge David Mather said a recent psychological report assessed Kannewischer as being at low risk.
"Because of his denial, age and health he is assessed as not suitable for any rehabilitation programme by way of group programme or individual psychological counselling," Judge Mather said in his parole decision.
"The psychologist recommends that the focus be on safety planning and release planning."
Judge Mather said the board had also considered the views of Kannewischer's victims - both in writing and in person at meetings before the hearing.
"The impact on them has been enduring and profound," he said.
"They are understandably concerned that Mr Kannewischer be released to an address near where they live."
But he would not be able to live anywhere near them when he was released - and that was not happening any time soon.
"There can be no question of him being ready for release on parole," Judge Mather said.
"We endorse the recommendation that the focus be on safety and release planning.
"Taking these matters into account, we decline parole."
Kannewischer will appear before the board again in July 2021.
At sentencing, Judge Michael Crosbie described Kannewischer's offending as "systematic abuse".
"You preyed on these defenceless young women when they were all at about the same stage of physical and emotional development," he said.
"Make no mistake, this is very grave offending."
The court heard from a number of women about their experiences with the offender.
The Otago Daily Times reported that one witness described being violated by Kannewischer while his own wife was in hospital giving birth.
Others spoke about Kannewischer repeatedly groping them.
One victim said the defendant would enter her room late at night and fondle her "quite roughly" on a regular basis.
"It seemed to go on forever," the woman said.
Another said after she was molested, Kannewischer forced her to lie on the floor where she was then raped.
Multiple victims said the defendant told them the lewd behaviour would help them "become a woman" and he would also warn them not to tell anyone about what had happened.
The victims read their emotional impact statements in court this morning.
"You stripped me of my childhood," one woman said.
She described a multitude of psychological problems suffered since the prolonged ordeal and said she had attempted suicide in the past.
Other victims sought refuge in alcohol and overeating to numb their pain, the court heard.
Judge Crosbie praised them for speaking "bravely and candidly".
"You are a strong formidable group of women and you are all survivors." he said.
Crown prosecutor Craig Power said Kannewischer was brazen and the effect of his offending was "lifelong and profound" for the victims.
He said the sex offender had no remorse and was assessed by probation as having minimal insight into his behaviour.
The court heard that Kannewischer had told a probation officer that one of the victims was his "favourite".
"There is a degree of flippancy and avoidance," Power said during sentencing.
SEXUAL HARM - DO YOU NEED HELP?
If it's an emergency and you feel that you or someone else is at risk, call 111.
If you've ever experienced sexual assault or abuse and need to talk to someone contact the Safe to Talk confidential crisis helpline on:
• Text 4334 and they will respond.
• Email support@safetotalk.nz
• Visit https://safetotalk.nz/contact-us/ for an online chat.
Alternatively contact your local police station - click here for a list.
If you have been abused, remember it's not your fault.
