DYFED-Powys Police have received "concerns" over spending by the Conservative Party in Brecon and Radnorshire during last year’s general election.
The force said it is talking to the Electoral Commission after concerns over spending by the party during the 2015 general election were reported to it.
The party has been at the centre of reports it allegedly broke spending rules in several key constituencies in England during the 2015 general election.
A police spokeswoman said: "Dyfed-Powys Police have received concerns in relation to the expenditure of the Conservative Party during the 2015 general election and we are consulting with the Electoral Commission."
The concerns relate to the Brecon and Radnorshire seat, which was captured for the Conservatives by Chris Davies, and other seats in the force area.
A spokesman for Mr Davies said: "All local spending was properly declared."
Mr Davies became the first Conservative to win the seat since 1992 when he beat Lib-Dem Roger Williams with a majority of 5,102.