Fiji's Ministry of Health says parents are being urged to take their children to the doctor if they start displaying symptoms of a mystery illness.
The viral infection begins with a fever, leading to rashes and blisters on the hands and feet and around the mouth and in severe cases the victim can suffer seizures.
Test results from Australia are due back within days to confirm exactly what the disease is.
A spokesman for the ministry, Peni Namotu, says parents need to take preventive measures like washing hands frequently and act quickly if symptoms get worse.
"Once your baby or your child have a fever and influenza like illness, seek medical treatment immediately because after that there's a high possibility of rashes developing and that's when the mystery virus comes up."
Fiji Ministry of Health spokesman, Peni Namotu