The Fiji Disaster Management Office says the small islands to the east of Viti Levu are likely to bear the brunt of Cyclone Tomas, though the storm has already caused significant damage in the eastern parts of Vanua Levu.
Operations manager, Anthony Blake, says on that island, trees and crops have been damaged, while there are problems with the water and power supplies.
He says in the smaller islands there are not large populations but their isolation will mean the first assessment of any destruction has to be completed quickly.
Mr Blake says the storm centre is not expected to come closer than 200 kilometres to Suva but it has a wide reach and the effects in the capital are already significant.
He says tonight's high tide will be closely monitored.
Police imposed a curfew last night and Mr Blake says that has been re-imposed this evening and will stay in place until 7am on Tuesday morning.
"This is done in the interest of the public so that they may stay confined to indoors and not roaming around the towns or streets in the central, eastern and northern divisions."