The government said the latest two cases include a three-month-old from Wailali settlement in Wainadoi and a 17-month-old from Wailekutu in Lami.
The 18 cases are from the Serua/Namosi subdivision, Suva and Rewa areas.
The health ministry said two days into a mass vaccination campaign had seen over 45,000 people immunised in the central division.
Meanwhile, all sporting tournaments and events in Fiji have been called off due to the measles outbreak in the country.