Philip Polkinghorne's sister has described a "catastrophic" scene upon entering his Remuera home on the day Auckland health manager Pauline Hanna was found dead.

Polkinghorne was acquitted of murdering Hanna, his wife, after a high-profile criminal trial in 2024.

He earlier told Coroner Tania Tetitaha at the inquest into his wife's death, which began in Auckland at the beginning of August, that he called his sister, Ruth Hughes, after he called 111.

Hughes lived nearby and arrived at the home before emergency responders arrived.

Giving evidence for the first time while under oath, Hughes said she found her brother cradling his wife on the floor.

"The first thing I saw when I entered was Pauline lying with her feet to the door. She was covered in a dressing gown or a blanket, and she was lying on her left ear. Pauline is quite tall, and her feet were about one and a half metres from the door which I entered through.

"Philip was in his dressing gown. He was wailing, and he had his head down and his arms around Pauline."

She said she also rang 111 to help direct emergency services.

"I asked Philip who he had called and if the police needed to be contacted. He said he dialled 111, but he said that he, quote: 'Can't even use his phone'. He said he had contacted them on a landline."

During his cross-examination, Polkinghorne's lawyer, Ron Mansfield, asked Hughes what that morning was like for her.

"It was so catastrophic. It was just utterly devastating. It's something I never wish to experience ever again, seeing my brother in the state he was in, seeing Pauline."

Some of Hughes' evidence cannot be reported because the media are prohibited from publishing details about a possible cause of Hanna's death, in accordance with section 71 of the Coroner's Act.

Hughes shared that she had a close relationship with her brother.

"My girls call him FUP, which stands for favourite Uncle Philip."

But she said her relationship with Pauline was "very light".

"We shared a medical partnership/friendship because of her work. A lot of the people she worked with at Counties [Manukau], I knew through my nursing experience.

"We used to give her a hard time about her cooking.

"She was just as people portray her: this very chic lady. I think she probably thought I was a little bit rough around the edges, but she adored Philip and he too. We used to say she was the glue for their family."