A farmer says he is "gutted" after losing around $50,000 worth of pregnant sheep in what appears to be a well planned and executed heist. The news comes at a time when Australian farmers are on high alert as sheep prices hit record highs and thefts increase.

Merino stud breeder Collyn Garnett is the second farmer to come forward as a victim to Gnowangerup police in the space of weeks, after Mr Garnett's neighbour Kevin Wise reported 80 wether weaners stolen a fortnight ago.

Authorities in Western Australia's Great Southern are grappling with a spate of thefts over the past month, including $7,000 worth of merino lambs reported stolen from a property in Bendering and $30,000 worth of woolly sheep taken from a Pingelly farm.

Although a stock agent put a value of $500 a head on Mr Garnett's missing pregnant ewes, the award-winning breeder said the crime cut deeper than a dollar figure.

"The money is not everything. I felt gutted actually, I felt violated … to know that someone has been into the farm," he said.

"The breeding is a lifetime's work not only for me but my father and grandfather, it's going to knock a bit of a hole in our breeding operation.

"It just makes you a bit wild that people think they are entitled to your livelihood."

On Thursday afternoon Mr Garnett brought the sheep in for shearing and realised he was short on numbers, having completed a full headcount two weeks prior.

"What we discovered halfway through the afternoon was that the shearers were going to run out of sheep," he said.

"Upon further investigation we found that one of the mobs was a bit over a hundred shy of the total.

"The shearers knocked off early and we went searching."

The search for the missing livestock turned up few clues for local police.

"They weren't in with another mob, all the fences were intact [and there was] no wool on the fences. We also couldn't see if there were any marks where the sheep had been yarded. My guess is they've been walked out onto a secluded road," Mr Garnett said.

"One night in particular we saw a set of brake lights on our private laneway. They had their headlights turned off but when they stopped to open the gate their brake lights came on and we went after them but we [didn't] find anything."

Mr Garnett's neighbour Kevin Wise has lost 100 out of 600 sheep from a single mob over a period of five months. ( ABC Great Southern: Mark Bennett )

Sheep theft on rise across country

Gnowangerup Police Sergeant Tracey Keown believed high prices for both wool and meat was driving theft in the region.

The veteran rural officer, who is investigating Mr Garnett's case, said she had never experienced so many sheep thefts reported to police in such a short period of time.

"Obviously there are stock losses every now and then … but not where we've had 100 missing here and 100 missing there," she said.

"These are not the only farmers in this area who have lost stock, there have been others close by … there have been other towns around us in this district where other farmers have lost sheep.

"This seems to be a concentration of stealing."

WAFarmers livestock executive officer Kim Haywood said livestock theft was a nationwide problem for Australian farmers, with reports on the rise in South Australia and tougher new penalties introduced in New South Wales to combat the problem.

"It's right across the board and across Australia, with the increasing value of sheep … stock theft is on the increase," she said.

Sheep in Australia must be tagged with National Livestock Identification Scheme (NLIS) ear tags, and under Western Australian law farmers are also required to mark their sheep with a unique earmark at around six months of age.

Although tags can be removed the notches taken out of the ear are permanent.

"Western Australia's traceability system is seen as probably one of the best in the whole country … unscrupulous people can cut tags out. That's why WA has a very robust backup system in mandatory ear branding," Ms Haywood said.

Sergeant Keown believed the missing sheep probably would not appear in regional saleyards, rather hidden in plain sight in paddocks on farms.

"I'd say people are taking them to maybe mix them in with their own sheep, maybe to bolster their flock numbers, possibly butchering some of them and shearing them and taking the wool off them," she said.

In August Western Australian saleyards were the focus of a joint operation between WA Police and the Department of Agriculture, monitoring if stock were being property identified and moved.

Sergeant Tracey Keown applauded Mr Garnett's decision to install security cameras on his property saying suspect licence plate numbers and vehicle descriptions are particularly useful to police. ( ABC Great Southern: Mark Bennett )

Police urge public to report suspicious behaviour

After several reports of around 100 animals being taken at a time, Sergeant Keown urged communities to be on the lookout for particular kinds of vehicles in the region.

"Large stock transport trucks take a lot more than that … so we're sort of thinking that the smaller vehicles [and trucks] eight-tonne trucks with crates on the back possibly are being used to move these sheep," she said.

"If there are any large vehicles like trucks, caravans or horse trailers anything of that sort that are carrying sheep that doesn't look right in our community let us know."

Mr Garnett, who has installed security cameras on his property, urged farmers to work together and with police to combat the criminals.

"The police in Gnowangerup are very good. They're also doing regular patrols. I've got very good neighbours and any information that we have we share and everyone is keeping an eye out that's for sure," he said.

"My advice to anyone who has sheep at the moment is if you've got gates that can be locked perhaps it's a good idea."

