The Batiki Nursing Station has reported the cases as rainwater supplies on the island continue to run low due to the dry conditions.
Emergency water assistance was delivered to Batiki yesterday, with the local boarding school and nursing station prioritised.
The Health Ministry says further water deliveries are expected from Levuka.
Clean water has also been brought from Ovalau to prepare oral rehydration solution for patients, while essential antibiotics have been made available at the nursing station.
Medical officers and health inspectors are also conducting health checks at the boarding school and assessing the safety of its water supply.
The Ministry is urging people on Batiki to boil drinking water for at least one minute, and use clean water for cooking and brushing their teeth.
People are also being advised to wash their hands properly with soap and clean water and keep water storage containers covered.
The Ministry says the driest period associated with the El Niño conditions is expected between October and December, and it is continuing to respond to the water shortage.
