The director of Tonga's disaster management office, Leveni Aho, says they remain concerned at the threat to Vava'u posed by Cyclone Winston.
The now category three storm is approaching the far northern Niuas after coming close to Vava'u overnight.
Latest projections are that it will then hook round and hit Vava'u again.
Mr Aho said there has already been some damage on Vava'u with trees and power down, obstructions on the airport runway, roads blocked and some houses have lost roofs.
But he said there has been no loss of life.
Earlier the cyclone brushed past Tongatapu and the Ha'apai group, causing minimal damage.
On Monday night it caused flooding and damaged crops in the southern islands of Fiji.
Winston now has average speeds of 120 kilometres with momentary gusts of up to 170 kilometres an hour.
Niue issues Tropical Cyclone alert.
A cyclone warning for Niue is in place with Winston expected to come within 160 kilometres of the island overnight tonight.
A gale warning has been issued for the island with winds expected to gusting up 100 kilometres an hour, with sometimes heavy rain and squally thunderstorms.
In the seas around Niue winds could reach 55 knots with damaging heavy swells.