The man pardoned of the murders of Jeannette and Harvey Crewe is convinced his wrongful convictions led not only to the demise of his first marriage but the cancer that killed his ex-wife.

Vivien Harrison, the former wife of Arthur Allan Thomas, was diagnosed with cancer 2 months ago and died on Friday at her home in Queensland. She was 68.

She was one of the central figures in one of New Zealand's most intriguing mysteries when Mr Thomas was wrongfully found guilty of murdering Pukekawa couple Harvey and Jeannette Crewe in 1970.

Mr Thomas was twice convicted of the murders and spent nine years in prison before he was pardoned and released in 1979.

He said his former wife's death was a shock and she "deserved to live a few more years".

Mr Thomas said his own plight was well-publicised but she had her own battle to fight, including the wrongful accusation that she was the mystery woman who fed infant Rochelle Crewe after her parents had been killed.

"But she didn't feed her a cracker, she was at home.

"People thought we were neighbours to the Crewes but we lived nine miles [14.5km] away."

Mr Thomas acknowledged the stress she was under during his imprisonment, something that dawned on him later in life.

"She never had much of a life," he said.

"I think she got the big C through the pressure of it all over the years. It takes a big toll on your life when you are wrongfully accused of something.

"She didn't have freedom. Neither did I, of course, but she would get all sorts of looks on the street and everything."

Despite their divorce just weeks before his pardon in 1979, Mrs Harrison always insisted her ex-husband was innocent.

Last year, she wrote to Justice Minister Simon Power pleading with him to appoint an independent investigator into the Crewe case - a request he declined.

"It's because she knew I was innocent of the crime, nothing else," said Mr Thomas.

"She divorced me, so she had nothing to lie about because she knew exactly where I was when the murders happened."

Her death leaves just one person still living - Mr Thomas' cousin Peter Thomas - who can verify his alibi that he was at home at the time of the Crewe murders.

Peter Thomas had been boarding with them at the time.

Arthur Allan Thomas said he was still struggling with the concept that Rochelle Crewe's calls for an independent inquiry into the murders of her parents had been declined.

Police have said they are reviewing, rather than reopening, the case.

"The police now should open the case and admit that they fabricated the evidence and that they perjured themselves in court.

"It's a hell of a thing to do but they have to open the case again."

Mr Thomas said he first met Vivien in the early 1960s on a Wellsford farm.

They were married in 1964 but separated and divorced during Mr Thomas' imprisonment.

Mrs Harrison later moved to Perth and the last time the pair spoke was at her aunt's funeral in the early 2000s.

Mr Thomas said he would like to attend the funeral service for his former wife but did not know where it would be held, and nor had he received an invitation to be present.

Mrs Harrison's uncle, Pat Vesey, said the false accusation against Mr Thomas affected her own reputation and "gnawed away at her all her life".

"She was guilty by association but if the person you are supposed to be guilty in association with is not guilty then it's a thousand times worse.

"Her pet phrase was that there were only three people who knew for certain, herself, Arthur and the detective [Detective Inspector Bruce Hutton] who led the case."

Mr Vesey was travelling to her funeral service today in Toowoomba, north of Brisbane.

He said her ashes would eventually be returned to New Zealand for burial near Whangarei.