The Kingaroy Stock and Rural Crime Squad says millions of dollars worth of livestock have been washed away after the January floods.
Detective Sergeant Mark Ferling says many farmers still have not found lost animals.
He says livestock needs to be returned to its rightful owners.
"I just hope people will do the right thing with livestock, they belong to somebody so all I ask for is if they can ring their local police and we can attempt to find the owners," he said.
"There is identifying marks on cattle where authorities can be alerted.
"It's hundreds of thousands of dollars, into the millions of dollars, worth of livestock that have probably strayed or gone missing since the flood event.
"There is a large number of livestock, cattle, pigs and sheep that have been washed away and also had a lot of fencing damage where livestock can stray ... and I just want people to keep an eye out if livestock do ... stray onto their property, that someone does actually own them and there are identification marks on most livestock that we can identify and get them back to their rightful owners."
© ABC 2013
16:49 EDT Tasmania is set for a wet and windy week as cold fronts batter the state in the upcoming days.