Police looking into the theft of cattle from an Ashburton farm say they do not have enough information to make any more progress on the investigation.
The theft of 500 dairy cows, estimated to be worth $800,000, was reported last month.
Police said they had spoken to a number of people, but could not take the inquiry any further at this stage.
A police spokesperson said the file remained open, in case any new information came to light.
The spokesperson said the investigation had established that the farm's auditing systems and processes may have been open to abuse.
"Police strongly urge all farmers to review their own business practices, systems and auditing processes to provide them with business reassurance and mitigate any potential risk.
"It is also a reminder for prospective employers to thoroughly check all potential employees' references and backgrounds before hiring."