Lake Hāwea residents are questioning why police didn't launch a homicide investigation until eight months after a woman died.

Invercargill woman Karen Gaylene White died at her Lake Hāwea property on 8 March. She was 60.

In November a homicide investigation was launched.

On Thursday, police said she died from injuries sustained in a significant assault.

Detective Senior Sergeant Regan Boucher said police were following positive lines of inquiry.

"Police believe people in the community hold important information about Mrs White's murder and we encourage those people to come forward."

Residents told RNZ that the community was shocked and they wanted to know how it took so long to become a homicide inquiry.

But they said they still felt safe in what was a small community of full time residents and holiday homes.

Boucher said police this week returned to examine the Lake Hāwea property with scientists from the ESR but would not reveal further details about their investigation or what was found.

In March, police initiated enquiries and treated White's death as unexplained, conducting a scene examination across the week that followed speaking with a number of people who may have been in the area.

Since then, police said they had been working to determine what occurred before her death and a homicide investigation was launched after their enquiries led them to believe she died in suspicious circumstances.