The controversial devices have been installed on Titchfield Park in Hucknall in a bid to prevent anti-social behaviour by teenagers.

But the use of mosquito alarms at the park's main pavilion has also angered families with younger children because there are fears the device can damage their hearing.

The device emits a high-pitched sound that is designed to disperse groups of teenagers.

The sound cannot usually be heard by those over 21 years of age and some retailers say it is useful against anti-social youths.

The alarms work on the basis that a person's ability to hear high frequencies tends to decline once they reach their 20s.

In February, the government refused to ban the alarms but said they should only be used as a last resort.

Ashfield Council confirmed that the alarms were in use at the pavilion on the park but refused to say how long they had been there.

They cost between £500 and £600 each and at least six are needed to make them effective in their targeted area.

Coun John Wilmott (Lab), of Hucknall, admitted he was surprised that one is in use on the Park Drive park.

He said: "It is a very controversial move. It is a new thing and it will be interesting to see whether it is a deterrent or not.

"It is a big statement to make that only people under 21 can hear it. Why won't it affect people who are 22 or 23?

"And will it affect people with hearing aids? How will it affect the hearing of young children?

"However the park is in an area that is subject to constant vandalism and graffiti. It is disturbing that youngsters are doing things like kicking and damaging the pavilion doors and smashing windows.Something needs to be done."

The Dispatch reported in May how security guards were to be brought in to crack down on anti-social behaviour by youngsters on the vandal-plagued park.

But Ashfield Council's head of neighbourhood services, Edd De Coverley, admitted they could do little in the face of large-scale vandalism or large groups of troublemakers.

The park is the town's premier open space and is the focus of a £2 million masterplan to bring it into the 21st century.

Hundreds of thousands of pounds have been spent on building two new pavilions, improving lighting and walkways, landscaping and a skate park.

The Dispatch has previously reported on vandals daubing paint on the pavilions, smashing windows, weather vanes and clocks, ripping up turf, setting fire to a cricket pitch and snapping sapling trees in half.

The Titchfield Park mosquito alarms came to light on a blog website that is tracking their usage.

The site also flagged up Beauvale chip shop on Beauvale Crescent and Hucknall's main tram station as two more locations where the alarms were thought to be used.

However Helen Kokkinou, owner of the chip shop, said: "The police said they were going to get us a mosquito alarm because we used to have problems with youngsters hanging around outside the shop on Friday nights and putting potential customers off. But they never came back to us."

Nottingham Express Transport, the company who run the county's trams, also denied there was an alarm at the station.