She suffered third-degree burns to her thumb and index and middle fingers, which were all eventually amputated above the middle joints.
WorkSafe's acting chief inspector Danielle Henry said the victim sustained life-changing injuries because the machine was not guarded to industry standards.
"It's highly disappointing that a company WorkSafe had seriously engaged with on multiple occasions still failed to take health and safety seriously, allowing its workers to operate dangerous machinery with no safeguarding," she said.
WorkSafe had earlier given Addiction Food NZ three improvement notices and one prohibition notice relating to health and safety systems.
"The issuing of four notices on other machinery in the workplace should have been a clear indication to Addiction Food NZ Limited that they needed to be completing full risk assessment of machinery before allowing workers to operate it," Henry said.
Addiction Food NZ operates New Zealand's largest export dry pet food plant, according to the Petfood Manufacturers Association.
Its website offers dried dog biscuits for sale with names including Outback Kangaroo Feast, New Zealand Forest Delicacies and Country Chicken and Apricot.
Its cat food brands include Duck Royale, Salmon Bleu and Viva La Venison.
WorkSafe's investigation, meanwhile, also found the company failed to ensure workers were properly trained or understood health and safety procedures.
"WorkSafe had given this company a clear directive to get its health and safety in order. It did not take appropriate action and a worker has needlessly suffered for their laxness."
