One of two Sydney women convicted over the euthanasia drug killing of former Qantas pilot Graeme Wylie has taken her own life.

Euthanasia advocate Phillip Nitschke on Friday said Caren Jenning, 75, overdosed last night with the euthanasia drug Nembutal, which is banned in Australia.

“She died last night after taking Nembutal,” Nitschke said.

“She left a detailed statement about the reasons why she chose to take this course.”

Jenning and her friend Shirley Justins were in June convicted of offences relating to the death of Wylie, and both women were due to face a sentencing hearing on October 7.

Justins, Wylie’s partner, was found guilty of his manslaughter, while Jenning was convicted of being an accessary before the fact.

The elderly woman, who had terminal cancer, admitted to the jury that she travelled to Mexico to obtain Nembutal for Wylie.

Nitschke, a close friend and supporter of both women, said Jenning’s statement had been handed to her lawyer, Sam Macedone, who would make it public on Monday.

“I think she will go down (in history) as a person who stood up for what she believed in,” Nitschke said.

Former Labor politician, Kep Enderby QC, said Jenning was “one of the finest women I have ever known”.

An attorney-general in the Whitlam government, Enderby said he met the former English teacher through his work with the Voluntary Euthanasia Society.

“She had an incredible reputation as a wonderful human being,” Mr Enderby said.

“Amongst people who understand things, who realise how bad the present law that covers voluntary euthanasia is, yes, she will be remembered very finely.”