Gardaí in Limerick have been taking a break from the stresses of policing one of Ireland's busiest cities – to act in Pat Shortt's new comedy series for RTÉ.

The show, called Mattie, tells the story of a hapless cop called Mattie Dwyer, who moves from the country to the city where a new collection of garda colleagues awaits him.

But when viewers see scenes shot around a mocked-up Garda station near Roxboro in Limerick, they should be aware that some of the gardaí seen on screen are not jobbing extras but real life gardaí.

"There are a great bunch of guards in Limerick, dedicated to their job but luckily also having a sense of humour," Shortt said. "They have been very helpful to us with uniforms and bits and pieces while we've been filming. We actually used a few gardaí as extras in their own uniforms turning up at the station to mill around."

"Officially, the guards really don't have an involvement at all. We sent them in a list of all our garda characters to cross-reference them with their list of gardaí and detectives in Limerick to make sure we weren't plagiarising anybody. We got a note back saying 'You have a PJ Somebody. Could you call him DJ?'"

Former D'Unbelieveable Shortt has defended his decision not to include storylines about the notorious crime gangs which have tarnished the city's image. "We're not Prime Time. We're a comedy show. People could assume this is about crime but it's actually about the characters and their relationships."

Penned by Shortt, co-writer Mike Finn and script editor David Cummins from BBC's Fast Show, the show is set to take Shortt's comedy in a new, less slapstick direction. A full series is expected next year.