The 90-year-old woman assaulted in a brutal home invasion in Levin has now died.

The elderly woman was left "smashed, bashed and left for dead" on November 2 after she opened her Bath St door to three young girls after one said she needed to use the toilet.

She was then allegedly brutally attacked before they stole items from the house. The woman was taken to hospital in a serious condition, however on Wednesday police said she has died.

Police say a homicide investigation has now been launched.

"The investigation is ongoing and we continue to make a number of enquiries," says Detective Senior Sergeant Craig Sheridan. "The next stage of the investigation will be a post-mortem."

Three young women previously arrested over the alleged offending remain before the courts.

Attack leaves Levin reeling

The brutal attack on the woman left Levin locals reeling, with one resident saying it has affected the whole community. 

"It's pretty tough and it obviously affects just about everyone, or it should do, in the community... they should feel pretty sad for that lady," he said.

Another resident said he was worried about his companion, who uses a wheelchair. 

"It doesn't make you feel very safe, does it? I mean it wouldn't make it safe for her in a wheelchair. I can't go out. She can't walk at all," he told Newshub.

Levin Mayor Bernie Wanden told Newshub he's disgusted.

"There are a lot of retirees in Levin who won't feel safe in their homes now."