POLICE are investigating after rustlers stole more than 80 sheep from fields.

A director of one farming union has described livestock thefts as "heartbreaking" for farmers.

Livestock are the fifth most stolen item from farms, according to NFU Mutual insurance which has said such thefts have been increasing in Wales.

The latest incident being investigated by Dyfed-Powys Police is of 84 sheep, including more than 60 ewes and 20 lambs, stolen from fields at Groesfaen, near Painscastle and Newgate, near Clyro.

The sheep were stolen over a 10 month period and police say they have little evidence to help them investigate the theft.

PCSO Jason Hawkins, of Brecon Police Station, said police are appealing for anyone who may have information to come forward but admitted thefts of livestock from the open countryside are hard to detect.

"There is no evidence, no witnesses and no CCTV and there is a large time frame for the offence," said the police community support officer.

"The farmer has gathered his sheep and realised he is 84 down. As the timescale is 10 months it could be some are taken on separate occasions or in one big go."

John Mercer, the director of farming union NFU Cymru, said livestock thefts are a problem for farmers.

Mr Mercer, who is based at the union’s headquarters on the Royal Welsh Showground in Llanelwedd, said: "Stock theft is heartbreaking when farmers have put a lot of effort into their stock and someone takes them.

"Sheep thefts are a problem and have been for a long time. We work hard with the police on various rural crime initiatives, such as farm watch, to try and get on top of the problem but unfortunately it does still happen.

"It causes a lot of anger for farmers who put a lot of effort into producing top quality stock."

The union has also tried to raise awareness among police of what they should look out for if the come across vehicles carrying livestock.

"We’ve tried to inform the police of what identification sheep should have and what paperwork should be carried."

Mr Mercer said stolen stock can be sold into the illegal meat trade. He said farmers can expect to receive at least £60 a head for lambs but said he doesn’t know what price they are sold for on the black-market.

He also acknowledged it can be difficult for farmers to monitor their animals - but thefts should always be reported.

"At this time of year when stock are out on the hills it can be a job to know when sheep have been taken but the advice is to always report every theft that way the police can build an accurate picture of the problem and identify areas where stock is being taken.

"People should also take a note of any unusual vehicles as it is better to be over-cautious."

Farm insurers NFU mutual has identified the cost of rural crime across the UK as £37.8m in 2014 with crime in Wales accounting for £1.7m of that figure. In Scotland the figure was £1.8m.

Tools are the most sought after item by criminals followed by quad bikes, oil and diesel and machinery followed by livestock.

NFU Mutual said figures from 2015 show livestock crime on the increase across Wales, the Midlands, the east of England and Northern Ireland and said criminals have moved around the country to target vulnerable communities.