Warning: This article deals with sexual abuse allegations. Helplines can be found at the bottom of the page.

A new complainant in the Peter Ellis case claims he raped her while babysitting and said if she told anyone she would die and "witches, demons and monsters would come".

Whether or not the court will accept and use the evidence from the woman - who said she was raped as a 4-year-old - in the upcoming appeal is being argued today.

Ellis died in 2019 at the age of 61, but the Supreme Court has granted leave for his appeal to continue despite his death.

His convictions, based on bizarre claims of satanic rituals, torture and sacrifice, have long been controversial due to failures in the investigation and justice processes used.

Ellis was released from prison in 2000, after serving seven years for abusing seven children at the Christchurch Civic Childcare Centre in 1991. He denied the offending.

In his application for leave to appeal to the Supreme Court, Ellis said the complainant interviews fell far short of best practice - even at the time of the alleged offending - and there was a strong possibility of contamination of the evidence.

He also argued the jury was not appropriately assisted at the trial by the expert witnesses.

The issue of the new evidence was introduced in November last year, but the matter was adjourned so police could do a full investigation into the new complaint.

Crown lawyer John Billington QC today summarised the complainant's evidence, which was that she remembered having a babysitter in the 1980s, when she was 4, who asked her to call him "Uncle Peter".

She said the man raped her and made her perform an indecent act, then told her if she told her parents "she would die, and witches, demons and monsters would come".

The girl did not tell anybody until she was about 15. At that time she reported it to police, though there is no record of this report.

She later saw Peter Ellis in a documentary in the 2000s and recognised him as the man who allegedly abused her.

She made another complaint to police after this, but said she did not want to press charges, Billington said.

The Crown did not become aware of the existence of the new complaint until September 2019, the same month Ellis died.

He was not given an opportunity to respond to the allegations before his death.

Billington said the new evidence could not have an impact on a verdict, and that it was up to the court to decide whether the evidence would assist the judges in assessing the memory evidence which would be brought forward in the full appeal later this year.

Ellis' lawyer Robert Harrison last year pointed to several issues with the new evidence, including that Peter Ellis' name was known across New Zealand by the time the woman complained to police, due to the creche accusations.

"I cannot believe that a complainant would have walked into a police station in 1992 and 1993 and complained about Peter Ellis sexually abusing them, and nothing happening."

He said the woman would have been the wrong age to have been abused by Ellis while he worked at the Civic Creche, and he said no other kindergarten had come forward to police at the time suggesting Ellis had committed offences there.

Today he said the woman's statement was inconsistent with earlier recollections she had given, suggesting her memory was "evolving".

For example she said she was unsure how Ellis came to be babysitting her, but later said she first met him at the creche.

"That flies in the face of what the Crown have found out when they went and interviewed people who had the records, and also I think one teacher who worked at that institution, and they are confident that Peter Ellis never attended at that creche.

"There is inherently no linkage of Peter Ellis having any association with this particular family."

Harrison said they could not let the evidence go before the court unchallenged, and he would need to be able to cross examine witnesses and put forth witnesses for Ellis to "reconstruct" his life in the early 80s, if the court decided to use the evidence.

He also said it was unfair to produce the evidence given police never put the accusations to Ellis to respond to before he died.

The court has reserved its decision.

The controversy

Ellis has always maintained his innocence and the verdicts in his trial have remained contentious - they have been described as being the result of mass hysteria in the book A City Possessed by Lynley Hood.

Hood criticised the convictions as a "witch hunt" at a time when hysteria around child abuse was sweeping the nation.

The original 16 charges were based on the preschoolers' testimony of satanic ritual abuse and torture.

Some of the more bizarre allegations included claims the children were made to strip and dance naked and were hung in cages.

Other allegations made by the children included having their genitals cut off, having sticks inserted into their bottoms, needles inserted into them, being placed in coffins, taking part in ritual killings and taking part in mock marriages.

Children also said they were forced to eat faeces and kick each other in the genitals as adults stood around them in a circle playing guitars.

There has been heavy criticism of the interviewing techniques used with the children.

Three convictions were overturned in 1994 after one of the children said she lied, but a second appeal against the remaining 13 convictions was dismissed in 1999.

After the second Court of Appeal decision there was a ministerial inquiry in 2001 by Sir Thomas Eichelbaum, which concluded there was no risk of a miscarriage of justice.

There have also been unsuccessful petitions to Parliament for a royal commission in 2003, 2008 and 2014.

Ellis died from cancer in September 2019.

Where to get 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 call the confidential crisis helpline Safe to Talkon: 0800 044 334 or text 4334. (available 24/7)
  • Male Survivors Aotearoaoffers a range of confidential support at centres across New Zealand - find your closest one here.
  • Mosaic - Tiaki Tangata: 0800 94 22 94 (available 11am - 8pm)
  • If you have been abused, remember it's not your fault.
  • Wellington HELP has a 24/7 helpline for people who need to speak to someone immediately. You can call 04 801 6655 and push 0 at the menu.