Detectives investigating the mysterious death of a former health boss have broadened their inquiries – interviewing a barber and a female masseuse known to her husband.

Pauline Hanna, 63, was found dead at the $4 million home she shared with her husband Philip Polkinghorne, who is a prominent eye surgeon, on April 5. The pair had been married for almost 30 years.

In a statement, police said almost five weeks on they are still treating the death as "unexplained".

The Herald has been told by a source that Polkinghorne was a frequent visitor to a masseuse based on Auckland's North Shore.

The person said his car – which has a unique personalised number plate – was often seen outside the property.

Polkinghorne would not comment on the claims when contacted by the Herald on Friday.

The masseuse has been questioned by officers investigating Hanna's death. The Herald has also been told that a barber known to the man has also been spoken to.

Police would not talk of the specifics of the inquiry, which has been dubbed Operation Kian.

Police and forensic units at the home shared by Pauline Hanna and her husband Philip Polkinghorne after her death, which is still deemed "unexplained". Photo / Dean Purcell

Detective Inspector Aaron Pascoe – from Auckland City CIB – said in a statement: "Police are continuing to investigate the circumstances of Pauline Hanna's sudden death, which we are still treating as unexplained.

"Our inquiries remain ongoing and police will not be commenting on specifics of our ongoing investigation."

Earlier this week, police and fire rushed to the plush Remuera home after reports of a fire at the property.

It is understood the incident involved a gas bottle which had accidentally ignited. No one was injured in the incident.

Hanna was found dead on the morning of Easter Monday.

The death sent shockwaves through the upmarket Auckland suburb after police swarmed the family's home on the public holiday.

Police cordons went up and officers went door-to-door asking residents if they had seen anything of not in the hours leading up to the woman's death.

Officers remained at the scene for more than a week after the death.

Hanna worked as a senior health manager, holding roles at the Counties Manukau District Health Board for the past 20 years.

She was working on the Covid-19 response when she died.

In his only interview after his wife's death, Polkinghorne told the Herald last month he was the person who found Hanna dead.

He said his wife was a "remarkable" woman who was adored by her entire family.

"Our relationship wasn't fine, it wasn't fine at all, it was perfect," he told the Herald.

The couple met through work and have three adult children from Polkinghorne's first marriage.

"The children are taking it one day at a time but we are all in shock. She was a lovely, lovely person."

Polkinghorne has described his wife as an incredibly hard worker and a "magnificent woman" who worked hard for her community.

Polkinghorne said Hanna worked all through Easter weekend but they were able to spend some time together on the Sunday.

The couple went to Highland Park where Hanna checked in on one of the Covid-19 vaccination stations before having lunch together and going home. After dinner, the pair watched television together and Hanna helped Polkinghorne write a letter.

"I said goodnight to her. I went to bed and she went to bed. That was the last time I saw her alive."

Family and friends farewelled Hanna at a funeral held at Parnell's Saint Mary's-in-Holy Trinity. The service featured moments with bubbles filling the air and a string quartet playing Vivaldi's Four Seasons during a photo tribute.

During the funeral, Hanna was described as a career woman who had spent 30 years in healthcare, and enjoyed cooking, reading and fitness. Noted for her elegance and style, she was regarded as a woman who could lend her hand to almost anything.

Taine Polkinghorne described his stepmother as the "glue" of the family.

Last week the Herald revealed the police inquiry had discovered Hanna had contacted a private investigator shortly before her death.

Several private investigators have told the Herald police had contacted them in a bid to confirm if Hanna had enlisted their services.

One investigator, who asked not to be named, said he received an email from a detective on April 12 - one week after Hanna's death on Easter Monday.

"It stated they had information suggesting that the deceased had engaged the services of a private investigator and had we worked for her - we had not.

"But there was also a note found at the house that said 'private investigator' and the name 'James' on it," he said.

A second private investigator said he was also asked if they had worked for Hanna.

"I remember getting a call about was she a client? Had she been a client? The answer was no," he said.

"I'd never heard of this woman before I read she had died in the papers."