The government has held a national emergency meeting ahead of the cyclone, United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said.
At present, the cyclone is classified as a Category 3 system, meaning hurricanes are likely, with roof and structural damage and power failures expected.
However, OCHA said forecasters are expecting tropical cyclone Ian to intensify to a Category 4 system by Friday evening. This means significant roofing loss and structural damage, caravans likely to blow away, dangerous airborne debris and widespread power failures.
Nasa has reported powerful thunderstorms around the cyclone’s centre and that an eye is developing, suggesting the cyclone is intensifying.