Police have executed a search warrant at the address of a "person of interest" in relation to the rustling of 500 cows from a mid Canterbury dairy farm.
They carried out the warrant at the Ashburton address on Friday. No arrests were made and the investigation is continuing.
The cows, which were from a rural Ashburton property, could be worth as much as $1m.
It is believed they were taken over several months.
Anyone with information which may help Police in their investigation can contact Canterbury Police on 03 363 7400 and quote file number 160825/1750.
Alternatively, information can be provided anonymously to Crimestoppers on 0800 555 111.