Detective Inspector Cameron Whiteside, whose rural investigation team is based out of Mudgee but has a team in Cootamundra and cover the Goulburn, Hume and Monaro districts, said criminal methodologies in livestock theft were changing as farmers had destocked due to drought and the summer bushfires.

"Stock numbers on farms are at historically low levels, and the stock that are there now on farms are a very valuable commodity," he said.

"What we've found that has changed is that criminals aren't going for using big stock crates and semi-trailers as they would before; they are often using smaller vehicles - utes, horse floats and even caravans - to sneak onto properties and grab a few livestock and get out.

"Stock theft is up by about 9 per cent across the state to the end of July this year."

Cattle, sheep, and goats are the main targets, and transportation of the stolen livestock using "gutted" caravans, which attract less suspicion as they ply country roads, is a new development by the thieves.

Across the southern region there have been 406 stock thefts in the past three years of approximately 20,354 sheep and 864 cattle, worth over $3 million.

"These criminals know what they are doing and are usually pretty experienced in stock handling; they watch a property for a day or two, see where the stock are located on the property and then go in at night and pull out small numbers," he said.

"But even those small numbers are very valuable in these times, as anyone would know from the butcher and [sale] yard prices; they [the criminals] either use them to build up their own herds, butcher them and sell the meat, or remove the tags to deidentify the livestock and hang onto them for a year or two before onselling them.

"These criminals are often playing the long game so that's what we have to do in trying to stop it."

Operation Stock Check was launched by NSW police this week, and Inspector Whiteside said people driving on country roads around the region in the weeks and months ahead could expect to see random roadside checking of any stock trucks, or vehicles towing floats or even caravans.

"Historically, there's not been been a lot of confidence among farmers to report the theft of small livestock numbers; they don't believe police are interested or are willing to follow up," he said.

"But that's starting to change as we've increased the size of our rural investigation teams; my officers are getting out around the sale yards and regional areas, working with local police and talking to farmers about what to look out for.

"This is all about disrupting criminal activity, and at the same time putting confidence back in the farmers and rural communities to report suspicious activity.

"I've found that farmers often have a pretty good hunch about these things; they see and hear suspicious things going on but often don't bother to report it.

"But as with most types of crime, the sooner it gets reported, the greater the chance we have of catching the criminals involved."

He said that at Berridale, south of Canberra, four carcasses were recently found. The animals had been stolen from a farm and butchered at a remote location.

He also flagged with horse, sheep and cattle owners to have their paperwork in order if they intend to transport livestock because if they are pulled over by police, they may be called on to prove the stock is their rightful property.