This week is Elder Abuse Awareness Week (June 15 to 22) and local advocacy and support groups say they are regularly receiving calls about the issue.
If somebody is being abused emotionally or financially by a family member they are often afraid to speak out because they could end up with further abuse, Custins said.
"If she allowed me to say anything about it, then she knew he was going to punish her eventually in some way because, well, I couldn't have known about it unless she told me."
Custins said victims of elder abuse often kept it to themselves for that reason.
"And you speak to them and you say, 'look, you must tell somebody, I'll tell somebody, and they go 'no, no, no, don't tell anybody because [they will] blame me'.
"Like all criminals – and it is criminal to do that, particularly to a parent – they don't want anybody showing them up, or … if there's money being siphoned off, then that stops their cash flow."
Custins said the increasing cost of housing was compounding the problem.
"A lot of children are beginning to put pressure on their parents to fund them getting into a house and saying 'well, you don't need to live in your big house, you could sell that'."
Age Concern New Zealand chief executive Stephanie Clare said the shame or stigma involved meant people did not always report it.
"This is one of the reasons it stays hidden. Many older people feel ashamed their own flesh and blood are treating them badly, so they won't talk about it."
In Tauranga and Western Bay, Whaioranga Trust has the elder abuse contract.
Alice Nuku, manager of the trust's elder abuse response service, said access had greatly improved since the introduction of the "Elder Abuse It's Not OK" helpline (0800 32 668 65).
She said across the wider Tauranga area there had been a steady increase in the number of families making contact via the helpline.
"A high number of calls involve elderly affected by or having the onset of dementia," Nuku said.
"Diminishing capacity to make decisions often results in sibling disputes seeking information to change agreed protocols.
"A much lower number of calls involve elderly affected by physical abuse or neglect."
She said more engagement with Māori and Pacific Island groups with low inquiry/referral rates was needed and so was promotion at cultural events.
Julie Sargisson, general manager of Alzheimers Tauranga and Western Bay of Plenty, said people living with dementia could be vulnerable to abuse.
Her team worked closely with the elder abuse response service when suspicions of abuse were brought to their attention.
Sargisson said her organisation's volunteers had been key in identifying abuse in several instances "and we ensure that they are trained to know how to respond appropriately".
Age Concern New Zealand elder abuse statistics •79 per cent of cases include psychological abuse •54 per cent of cases involve financial abuse •76 per cent of alleged abusers are family members •60 per cent of alleged abusers are adult children or grandchildren •Alleged abusers are as likely to be female as male.
Where to get help •You can phone the 24/7 'Elder Abuse It's Not OK' helpline on 0800 32 668 65 to connect with the local elder abuse response service. •Age Concern Tauranga (07 578 2631) also has a number of services providing support to people feeling lonely and isolated. •Those include an accredited visiting service, coffee and conversation groups, and a monthly meeting. •You can also phone Alzheimers Tauranga and Western Bay on 07 577 6344 and Tauranga and Western Bay Greypower on 07 571 2558. •Whaioranga Trust can be contacted on 07 544 9981.