North Wales Police are urging people not to give out their bank details over the telephone.
The warning comes from Inspector Lisa Surridge following two incidents in the Flint area over the last couple of days.
Inspector Surridge said: “Two elderly men, one in his 70’s and the other in his 80’s were contacted by someone on the telephone who said that they were from the Nat West Bank, Flint. They were told by this person that he needed their bank details to enable him to issue new bank cards.
“The elderly people gave him their details and as a result one of them has had a significant amount of money taken from his account.
“We are now investigating and urging people to be extra vigilant and under no circumstances to give out their bank details over the telephone, “she said.
Anyone who may have also been contacted by this person or has any information is asked to contact North Wales Police on 101 (if in Wales) or 0845 6071001 (Welsh) 0845 6071002 (English) alternatively text 66767 or Crimestoppers Wales/Cymru on 0800555111.