Elderly people are having their children move back in and are being threatened with a lack of contact with grandchildren if the "takeover" is challenged, Senior Citizens Minister Maggie Barry says.
Age Concern says it is not uncommon for its workers to encounter such cases of elder abuse and the frequency will only increase with an ageing population and people struggling with increasing house prices and rents.
The organisation delivers 19 of the Government's elder abuse and prevention services and deals with about 2000 cases a year - eight referrals each working day.
Elder abuse is an umbrella term and can be physical, financial and psychological.
Chief executive Robyn Scott said their workload was likely to be the "tip of the iceberg".
It is estimated that between 17,000 and 25,000 older Kiwis experience some sort of abuse each year. About three-quarters of alleged abusers are family members, meaning cases often go unreported.
Financial abuse accounts for about half of all cases.
"There is a kind of attitude that 'we are entitled to this money', and that an older person is just an older person - that they don't have the right to self-determine where their resources go," Ms Scott said.
"It can be the unauthorised taking of money or possessions, or families moving back into somebody's house and then shunting the person to the back-end of the house."
Ms Barry released the 2014 Report on the Positive Ageing Strategy last week that found that each year about 3-10 per cent of older people are subjected to physical, psychological, sexual or financial abuse, and predicted that rate would increase.
She told the Herald that it was both a growing and sensitive issue.
"It's horrifying to hear that children move back into Mum's house, they don't pay their way, they might have their own families with them, and they kind of take over, and make the older person feel they are not so worthwhile.
"If people do talk about it then perhaps they won't see their grandchildren again, or they will be left by their own children, and then they will be isolated and very unhappy. So I can understand their problems, but we need to get it out in the open.
"I'm trying to encourage people in this over-the-back-fence, neighbourhood approach, to look out for each other more, because then you can see if someone is miserable and unhappy."
Ms Scott said that in many cases an older person wanted to have their family move in, or it was done in order to care for them.
But if it was not wanted and amounted to abuse there were likely to be signs.
In the worst cases elder abuse is prosecuted. Hawkes Bay woman Joanne Quinn was jailed last year for neglecting her 82-year-old mother, found embedded in a couch with rotting leg wounds.
But Age Concern attempts to resolve many cases without legal action.
Before the last election Labour promised to establish an Aged Care Commissioner to investigate claims of elder abuse, neglect and financial mismanagement, which it said was a response to requests from Grey Power and the Aged Care Association.
Ms Barry said raising awareness of elder abuse was a priority.
"I think it's a matter of trying to get people to come forward, that's been the difficult part. But certainly it's pretty apparent when a bank balance goes down dramatically ... they are able to be prosecuted."
Financial exploitation common
One elderly person's children and grandchildren - all adults - moved into her house without paying rent.
The new arrivals then used their relative's pension to pay for their own expenses, said an Age Concern worker.
"There are also [cases] where they are presenting legal documents saying, 'I've drafted up your will, Dad, can you sign that,' and [the elderly] are very much taken advantage of financially in that way as well," said the social worker, who asked to remain anonymous because of the sensitivity of her work.
Financial abuse cases were common, she said, and more often involved family members who were not living with the elderly person. Psychological abuse - such as constant belittling and putdowns - was also frequent.
"The biggest one I see, which I think is discounted more than anything, is them having their decisions made for them by family members and also institutions."