There are also suspicions she may have fatally poisoned her husband nine years ago. Graham Edward Dawson, 54, died in Christchurch Hospital from multi-organ failure in September 2009.
After her current partner was hospitalised, it was found his blood contained five types of prescription medicine.
A large stash of drugs – described as "a suitcase full" – was also discovered at Dawson's home, Stuff reported.
After being discharged, the partner consulted lawyers and police discovered Dawson had taken out a $350,000 insurance policy on his life.
Shelagh Dawson's children have tonight defended their mother and rejected what they label unsubstantiated allegations relating to poisoning.
In statement to Stuff, the children said their father's death was the result medical misadventure following a routine colonoscopy.
Graham Dawson's death certificate reportedly stated he died from multi-organ failure.
The children said there was no suggestion of foul play and "no evidence of drugs in his system".
They added that their mother and the former partner tried to take out life insurance policies together but only his was approved.
The children stressed that no charges had been laid against their mother.
However the former partner told Stuff he chose not to publicise documented "proof" of his poisoning in order to protect Dawson's reputation.
"They [the children] are hurting. They're trying to protect her. They're not going to believe their mum has done anything bad."
He said a witness saw part of the alleged poisoning incident - when he is understood to have woken in his hospital room and seen Dawson administering a substance to his IV line through a needle.
It was "bloody good" to be alive, he said.
Dawson's sister told Stuff Dawson was not malicious or vindictive. "She was just an outgoing, talkative type of person ... friendly and sociable.
"She's passed away ... how can she defend herself now?"
Police today refused to comment today on the investigation, dubbed Operation Medway.
People close to Dawson today declined to comment when approached by the Herald.
University of Otago, Christchurch confirmed that Dawson, a nurse with a PhD gained in the United Kingdom, was employed at the University of Otago's Christchurch campus between November 2004 and March 2009.
During her employment with the university, she was "not in positions with direct contact with patients, research subjects or medication", a spokeswoman said.
"Her first role with the Christchurch campus was as a research fellow with the New Zealand Health Technology Assessment group," the spokesman said.
"In her role with this now-defunct group, Dawson reviewed data relating to the prevalence of common conditions. She reviewed non-identifiable large data sets not individual patient records, and had no patient contact."
Dawson's second role at the university was as a lecturer of postgraduate nursing students. In that role, she gave lectures to nursing students and assessed their assignments.
A spokesperson for the coroner's office confirmed the Dawson case was active and investigations were continuing.
