Northland's medical officer of health says a cluster of recent salmonella poisoning cases may have been linked to a food outlet.
Clair Mills says nine of the 11 people poisoned between mid-April and early May ate at the same food outlet in Whangarei.
Dr Mills has not named the outlet but says food samples have been taken.
The bug has been confirmed as salmonella infantis, which Dr Mills says is uncommon in the region.