They are pleading with the Government to investigate the source of the constant, pulsating, low-frequency noise that cannot be traced despite repeated efforts.

Frustrated locals in a rural part of Beaufort, 15km from Killarney, have been hearing the bizarre noise since early last year but cannot find what is causing it.

Resident Barry Lynch said: “The first time we heard it was in Apr 2011 and it has been there 24/7 since then. We are nearly gone out of our minds because we can’t get a decent night of sleep and it’s there all day, every day.

“There are no mobile phone masts, windmills or generators in the area and the ESB has assured us that the problem is not due to any high-tension wires in the area.

“We thought the noise might be coming from water pumps installed in the area by Kerry County Council but an engineer switched the pumps off for a trial period and the noise was still there.”

He said that neighbours over a 7km radius have also complained about the sound.

“One neighbour went to the doctor because he thought he was having a problem with his hearing. It is placing a huge strain on my own partner who can’t sleep at night, even when she wears earplugs.”

Mr Lynch said the noise was even more noticeable inside his home and despite extensive insulation, the whole building appears to vibrate, particularly in the stillness of night.

“The whole thing is very unpleasant and it is really bothering us. We don’t know what we can do. We are pleading with the Department of the Environment or some other organisation to help us before we are driven out of our homes,” said Mr Lynch.

“Not everybody in the parish has heard the noise but just because they can’t hear it doesn’t mean it isn’t there. Our neighbours and ourselves can hear it the minute we step out of our cars and it’s there all the time until we drive off again.”

He said he had found out a similar mystery noise had been reported in many parts of the world.

It has become known as “The Hum” and is described in some reports as a worldwide phenomenon involving a mysterious, persistent and invasive low-frequency humming noise.

Complaints have been received from residents in several locations around the globe, including England, New Mexico, and New Zealand.

“It’s absolutely wearing us down and we are crying out for a good night’s sleep before our health starts to give,” said Mr Lynch.