Elderly Levin residents are being urged not to open their door to strangers after a 90-year-old was attacked in her home on Saturday afternoon.
The elderly woman remains in a stable condition in Palmerston North Hospital. On Sunday, police said she had serious injuries.
Three teenage girls have been arrested in relation to the assault.
They have been charged with aggravated robbery and are due to appear in the Youth Court in Levin today.
Police said the woman's family were rallying around her and providing support.
One neighbour, describing himself as a distant relative, said some people had knocked on the woman's door and asked to use the toilet before the attack took place.
Horowhenua Grey Power president Terry Hemmingsen said elderly people in Levin had increasingly been reporting that people had been knocking on their doors, sometimes late at night.
The incidents had left many feeling harassed and tormented but they hadn't been reporting them to police, he said.
"It's important [older people] tell the police what's going on so the police can be a wee bit more proactive."
As a safety measure elderly Levin residents should not open their door to strangers, he said. "Be more cautious ... don't let anybody that you don't know inside."
Grey Power was talking to older people about home security and had brought in people from security companies to give advice, he said.
Neighbours of the Bath St woman spoken to by RNZ were shocked at the attack and could not believe such a thing could happen in the town, while comments on neighbourhood social media groups expressed anger.
Horowhenua Mayor Bernie Wanden said the community was appalled and very saddened.
He understood Grey Power's worries but said for a number of years there had been a positive aging plan in the area to support the elderly population.
"We know that there are some vulnerable people out in our community, and we in our community probably need to step up and offer them the support and care where we can.
"We have a large part of our population which is elderly and we know that they need to feel safe and they need to be resilient in their own homes as much as they can.
"The community I'm sure will, after this incident, take much greater care in trying to assist those people where they can."
Officers have been standing guard at the house behind a cordon that was expected to stay in place until later today.
Detective Senior Sergeant Craig Sheridan said at the weekend police were pleased to have been able to make swift arrests "to provide reassurance to the victim, her family and the wider community, who are understandably shaken by this incident".