Sex workers are blackmailing and exploiting elderly men in a saga of sinister and humiliating abuse.

The often unreported issue is a dark secret of elder abuse and victims come forward only when they are desperate, an expert says.

Age Concern Canterbury community health nurse Kerry Howley has worked with the victims of elder abuse for six years and has her fair share of horror stories.

Examples she gave to The Press included:

Brent, 72, had been regularly using the services of a prostitute who one day knocked on his door claiming to be carrying his baby and demanding he pay child support. He rang Age Concern for help, saying he "physically" could not be the father of the child. When Howley rang the sex worker, threatening a paternity test after the birth, "she backed off completely and said it wasn't his baby".

Frank, 68, lost "pretty much everything he owned" after he befriended a prostitute. She knew where he kept his spare key and over several years she bled him of all his money, pain-killing medication and most of his furniture - even taking his recliner chair, that he was still paying off at Noel Leeming, and leaving him with only a stool in his living room.

Ivan, 79, called on a prostitute in her early 40s who now visits him at least twice a day, threatening gang affiliations if he does not hand over money. He has lost his entire retirement fund of $100,000. "He had quite a nice little nest egg of over $100,000 and now it's all gone. He would have been right for retirement if this woman hadn't come along and forced him to give it all away under influence and threats." Ivan went to Age Concern for help and police were contacted but he has since "gone underground" in fear of the woman's gang connections. "He is afraid if we stir the pot or talk to her that something terrible will happen to him so now he is suffering in silence and there is nothing we can do about it."

All three men sought out simple affection from the women who sell sex. And it nearly cost them everything.

Elder abuse was most commonly carried out by family members, but, Howley said, "opportunistic" strangers also preyed on the elderly.

Some of those strangers were sex workers who manipulated lonely elderly men seeking affection and companionship.

Howley was aware of five elderly men who were exploited by prostitutes and said they had come forward only "once they had hit complete crisis point". "It is so humiliating for them to speak out that I don't think we will ever know the full extent of this issue."

One prostitute, known to police, had five elderly men "on the go", four in Christchurch and one in Ashburton.

Howley believed the elderly men were contacting the women through advertisements in newspapers, not necessarily for sex but often just companionship.

The women first started taking the money for services but later used "sob stories" or intimidation.

Of the five cases she was aware of, three had threatened gang affiliations. "The men feel hurt, ashamed and deceived as they believed this person was a good person. It's so sad."

New Zealand Prostitutes' Collective regional co-ordinator Anna Reed was aware of sex workers abusing the elderly but said it was uncommon. One "older" client had contacted the collective for help when a prostitute started to "blackmail" him for money and other cases involved prostitutes falsely accusing men of impregnating them, she said.

Police had been involved in a handful of cases over the years.

"Unfortunately there are unscrupulous people in all walks of life. It is rare, but it has happened and it is not just confined to the sex industry." Reed believed sex workers could potentially take advantage of elderly men because it was unlikely they would go to police as "it is a very embarrassing situation".

Police Canterbury prevention manager Inspector Richard Bruce said police worked closely with Age Concern. He urged the community to be "on the look out" for any evidence of elder abuse. Any signs of missing cash or property, excessive use of credit cards or any strangers regularly turning up on an elderly person's doorstep should be reported.

- © Fairfax NZ News