Detective Senior Constable Richard Hughes, of the Warrnambool police crime investigation unit, said the 49 white lambs were removed from a Berribank property between 8pm on Monday this week and 6.30am on Tuesday.

The lambs valued at $165 each were taken from the farm on the Hamilton Highway at Berribank, between Lismore and Cressy.

A farm manager told police the offenders entered a paddock off a laneway after opening two gates and loaded the lambs from a 35 hectare paddock.

The lambs weigh between 44 and 65 kilograms and would have been loaded on to a truck.

"The farm manager said the night the lambs went missing it had been raining and her saw fresh tyre marks near the open gates the next morning," Detective Senior Constable Hughes said.

"The 1500 hectare property is quite isolated and we assume that mobile loading equipment would have been used to facilitate the theft."