A properly funded welfare-based programme to neuter tens of thousands of feral or "wild" cats needs to be introduced urgently, according to animal welfare campaigners.
Jimmy Cahill, general manager of the Dublin Society for the Prevention of Cruelty to Animals (DSPCA), said that up to 400,000 of the estimated one million feline population in the Dublin area alone are feral.
Such animals can engage in inbreeding, leading to genetic problems and diseases and a poor quality of life. There is a risk the public, including children, can contract "zoonotic" animal-to-human diseases from their faeces.
But due to a lack of any legal requirement for local councils to deal with this, both Mr Cahill and the Irish Society for the Prevention of Cruelty to Animals (ISPCA) say there has been a significant increase in feral cats.
Both groups say the problem is often compounded by well-meaning individuals feeding unneutered cats, which continue to breed. Mr Cahill said a typical healthy male and female cat and their offspring can produce 52 kittens within 12 months. He estimated it would take five to seven years to get Dublin's feral cat problem under control.
"People have no problem if there are one or two in an area, but when there are 15 or 20, that's when it becomes a real problem," he said. "All it takes is for two or three people to feed them . . . They should call us or other welfare organisations to try to have the animals neutered."
Calling for "proper" Government investment to allow charities such as his own to address the issue - rather than pest control companies or the council - Mr Cahill said once a feral cat is humanely trapped, they are typically neutered and placed back in the area from which they came.
The DSPCA trapped and neutered some 450 feral cats last year.
Mark Beazley, general manager of the ISPCA, said the growth in the feral cat population is both an environmental and social issue. His association often receives calls from local residents asking for a colony of feral cats to be removed.
He noted that among the diseases they can contract are feline aids and cat flu, which can place domestic cats at risk.
Other public health concerns include the possibility of zoonotic diseases being transmitted to humans from cat faeces.
"Cat faeces, like any faeces, contain bacteria . . . For example, worm eggs can live in the soil for a long time and can be ingested by children," said Mr Beazley.
Florence O'Sullivan, of the Cats and Dogs Protection Association, said feral cats can play a useful role in controlling the rat and mice population in an area.
"We are out seven days a week trapping feral cats . . . Perhaps three generations ago, they were somebody's pet," she said.