The crook has been spotted in several parts of the county over the past few days.
He claims to be collecting cash for the missions – and a number of elderly people in isolated communities have handed over cash.
Well-known Garda Crime Prevention Officer Sergeant Paul Wallace today asked neighbours to be on the look-out for the conman who is believed to be driving an English-registered white saloon car.
“Anyone who sees anything suspicious should note the registration number and pass it on to local gardai,” said Sgt Wallace.
He said the thief is choosing to operate in isolated rural areas in a bid to avoid suspicion.