Image caption This year's National Eisteddfod in Powys starts with an opening concert on Friday night

An "indecent" novel entered into a National Eisteddfod writing competition has led to a police investigation.

North Wales Police confirmed it is investigating a piece submitted for the Daniel Owen Memorial Prize under the Obscene Communications Act.

The piece was sent to the National Eisteddfod's office in Mold, Flintshire, and officials handed it on to police in March.

Officials said the novel refers to "criminal" acts and caused "concern".

Det Ch Insp Iestyn Davies said: "The work concerned has been assessed as being offensive and indecent in its nature and is being investigated as an offence under the Obscene Communications Act."

Speaking on BBC Radio Cymru, the National Eisteddfod's chief executive Elfed Roberts said: "The novel referred to acts that are bluntly criminal."

He added: "When you know that the work is against the law - then there was no other option but to take action."

Mr Roberts added a false name and address was supplied by the entrant.

The Daniel Owen Memorial Prize is given annually to a novel of no less than 50,000 words and carries a £5,000 prize.