An introduced species of gecko has fried the air-conditioning system of a nursing home in northern New South Wales, causing thousands of dollars in damage.

Key points: Asian house geckos are one of the most successful invasive house species in Australia

Asian house geckos are one of the most successful invasive house species in Australia They were first found in Brisbane almost 40 years ago and have spread in their millions since then

They were first found in Brisbane almost 40 years ago and have spread in their millions since then Experts say there is no getting rid of them and that air-conditioning units are an ideal hiding place for them, safe from predators

The management of the 98-bed Raffles nursing home in Tweed Heads said it received a repair bill of $2,500 after geckos short-circuited the electrical system within the air-conditioning unit.

Leah Bartholomew, whose father Don has a room at Raffles, said the destructive geckos were the talk of the aged-care facility.



"We weren't worried about dad because the staff are great," Ms Bartholomew said.

"But it was really hot and it is hard to believe these little lizards can cause so much damage, which isn't covered by insurance because they are considered vermin."

Main culprit in air-con malfunctions

Gecko eggs found inside the air-conditioning unit. ( Supplied: Darrell Kellahan )

Repair specialists say there is a growing trend of invasive Asian house gecko destroying cooling systems across New South Wales and Queensland.

Tweed-based electrical repairer Laurie Cooper said when he started out 47 years ago, geckos were not on the radar.

The air conditioning at Raffles nursing home at Tweed Heads was put out of action as a result of geckos. ( ABC Gold Coast: Gemma Sapwell )

Now they are the main culprit in malfunctioning air-conditioners.

"Even before we go out on a job, when people ring us my first question is, do you have geckos?" he said.

"It's the number one problem causing the failures.

"They're wreaking havoc, they're a menace, if you have a way to get rid of them, we're all ears."

Moth balls not a deterrent

Air conditioning specialist Darrell Kellahan, who services the Gold Coast and surrounding areas, said the moisture from the lizard is what usually causes the problem.

"They crawl over the electrical circuits, they urinate on the boards and they get electrocuted, they cause damage that way," he said.

An Asian house gecko. ( Supplied: Queensland Museum )

Mr Cooper said he had found it difficult to come up with ways to prevent geckos from entering air-conditioning units, with some suggestions failing spectacularly.

"After a business client had an issue with gecko damage, I called Tweed Council asking for advice and they told me to put naphthalene, like in moth balls, into the air-conditioner," he said.

"We repaired it, but within a month the owner rang us to say it wasn't working again, when I went in I lifted the lid and the actual geckos were running across the naphthalene flakes so we found that not to be a deterrent at all," he said.

Both Mr Kellahan and Mr Cooper said while they have not found a way to keep the pests at bay, they have had some success in reducing damage by spraying the electrical circuit boards with an anti-corrosion spray during installation.

'No amount of manual removal will help'

Dr Conrad Hoskins from James Cook University, who has been studying the impact of the Asian house geckos on native animals, said geckos are attracted to air-conditioners because they provide a perfect hiding place.

"They just like any crevice," Dr Hoskins said.

"It's a nice structure where predators like snakes and cats can't get them when they're tucked away."

A pair of Asian house geckos ( Supplied: Eric Vanderduys )

Dr Hoskins said the lizard had rapidly spread since it was first found in Brisbane almost 40 years ago.

"They've done really well in suburbia and they're getting into much bushland in huge numbers," he said.

"There can be hundreds of thousands of them in a national park."

As far as trying to make your home gecko-free, Dr Hoskins said forget it.

"Even if you removed all the Asian house geckos off your house, within a year or so you'd have just as many because there are million and millions of them, no amount of manual removal will help," he said.