A fifth person has contracted Hepatitis A after eating a mixed berry product, Ministry of Primary Industries confirmed.
"All five people who have fallen sick with Hepatitis A have the same strain, and all five have consumed the Fruzio Mixed Berry product recalled this month," Ministry of Primary Industries (MPI) plants food and environment director Peter Thomson said.
He said the investigation was ongoing and they weren't ruling out the possibility of further recalls.
Mr Thomson advised people to wash their hands before eating and preparing food.
Anyone who was concerned should briefly boil any frozen berries before eating them, or ensure cooking exceeds 85C for one minute.
Elderly people and those with chronic liver damage should avoid imported frozen berries that have not been heat treated.
If concerned about a potential risk, seek advice from a medical practitioner, or call the Ministry of Health's Healthline on 0800 61 11 16.
Those concerned about the safety of food products, should contact the MPI consumer helpline 0800 00 83 33.
Products under recall
• Fruzio Mixed Berries 1kg and 500g products, which contains strawberries and blackberries
• Fruzio IQF Strawberry 1kg
• Fruzio IQF Blackberry 1kg
• Fruzio IQF 3 Mixed Berry 1kg (blackberries, strawberries and blueberries).