Sydney - The prime suspect in the murder of New Zealand-born nurse Michelle Beets has gone public to profess his innocence.

The 48-year-old man, who has been spoken to twice by police in relation to the slaying of the 57-year-old nurse on her porch on April 27, insists he is not her killer.

"The police have their mind made up that I did something, but I didn't," the man said in an interview with The Daily Telegraph newspaper.

The trained nurse from an unspecified country outside Australia is living in a Sydney hotel room while a police forensic team combs his north Sydney apartment for clues.

He denies playing a role in the death of Ms Beets, who was stabbed when she returned home from work by an assailant who was seen running from her property carrying a backpack.

"I'm not a killer, OK, and I would certainly never harm a woman," he told the newspaper.

"The police think that just because I have a military background, that I am a killer. I'm not."

The man said that on the night Ms Beets was killed he met his wife at a nearby train station after she returned home from work and they walked home together.

He said police told him they had CCTV footage of him throwing a backpack into a rubbish bin at a local shopping centre, but he insisted that was coincidental.

"I was always going to throw away that bag, it's no big deal," he said.

"The police have their mind made up that I did something, but I didn't," said the man, who has not been identified.

Police believe Ms Beets' killer worked with her at Royal North Shore Hospital where she managed the emergency department.

The man confirmed he arrived in Sydney in February last year and was contracted by the hospital to work for 12 months.

"That's the crazy thing, if anything I am grateful to Michelle because she gave me my job," he said.

During the year he worked at the hospital the man said he could recall seeing Ms Beets a handful of times and denied they had fallen out.

Ms Beets was farewelled in north Sydney last Friday at a funeral attended by more than 1000 mourners.

Police continue to search for the murder weapon.

- NZPA