It's been revealed another person may have contracted hepatitis A from Fruzio frozen berries.
Last week, the Ministry for Primary Industries (MPI) recalled Fruzio mixed berries from all supermarket shelves.
So far four people have been confirmed to have contracted the virus from the product.
Test results from the latest case will be confirmed later this week.
"MPI was alerted to the case yesterday evening, following an investigation by the Ministry of Health and Environmental Science and Research (ESR)," says MPI's director of plant, food and environment Peter Thomson.
"In the new case, the person ate the berries in late October and reported symptoms at the beginning of this month. The person was briefly hospitalised for observation, but released the same day."
Mr Thomson says MPI has an extensive investigation and work programme underway in relation to the frozen berries.
People concerned about a potential health risk are asked to seek advice from a medical practitioner, or call the Ministry of Health's Healthline on 0800 61 11 16.
People concerned about the safety of food products should contact the MPI consumer helpline on 0800 00 83 33.