Children who attended a South Auckland school dental clinic over the last four months may be at risk of contracting Hepatitis B, Hepatitis C or HIV from unsterilised water.
Kids who attended Pukekohe Intermediate Dental Clinic between September 13 last year and January 23 this year could be at risk of exposure to the contaminated water.
Counties Manukau Health (CMH) say they will be contacting parents and caregivers of children affected for screening.
"There is a very small chance that children who had particular procedures may have been exposed to unsterilised water, possibly containing blood or saliva from other children," a CMH spokesperson says in a statement.
Tests will be conducted for children who have undergone procedures involving compressed air, a drill, extraction or suction.
The CMH says specialists will be offering the affected children blood tests for viral infections including Hepatitis B, Hepatitis C and HIV.
They say the risk of such infections is "very low as it is extremely rare for New Zealand children to have any of these conditions".
"A number of children, especially pre-schoolers, will have had only had a visual examination and because they have not come into contact with the problematic equipment, may not need blood tests. Some children may also need catch-up immunisations against Hepatitis B," Chief Medical Officer for CMH Dr Johnson said.
"The problem occurred due to equipment assembly and is not related to the clinical practice of the dental staff at the clinic, or the high quality care given to children across Auckland."
An investigation has been launched over the contamination scare.
CMH say they urge anyone with concerns over the matter to contact Healthline on 0800 611 116 or talk to their GP if they require further information or support.