A Villa Maria spokeswoman said a person suffered an electrical shock at the Omahu Vineyard site on Wednesday morning.
"The person has been taken to hospital for precautionary measures and we understand they are likely to be discharged later today," she said.
"The incident has been referred to WorkSafe NZ, who we are working closely with and we are conducting our own internal investigation into the incident."
WorkSafe said they have been notified of the incident and are making initial inquiries.