Cyclone Wilma has moved past Tonga's main island of Tongatapu and was heading southwest into open waters on Tuesday night.
The hurricane warning previously in force for much of the Pacific Island nation has been cancelled, though gale-force winds are still expected as the cyclone moves away.
Earlier, the Category 3 storm passed to the eastern side of Vava'u before directly hitting the Ha'apai islands where high winds and big waves damaged buildings and wiped out crops.
There are reports of major damage to schools, buildings and fishing boats, but no reports of casualties. The governor's residence has also been damaged, while two town halls have collapsed.
Tonga's Nuku'Alofa International Airport was closed on Tuesday.
Some islands in southern Fiji are also expecting bad weather as the cyclone moves past.
Wilma has already passed through American Samoa and Samoa.
Luxury resort battered
A luxury resort in the Ha'apai group was feeling the effects of the cyclone.
Boris Stavenow, owner of Sandy Beach Resort, says the while winds of close to 100km/h were strong, it was the waves combined with a high spring tide that did the most damage.
Mr Stavenow says guests from a neighbouring resort were evacuated to his resort which has more stable and solid buildings after some accommodation was washed away.
Power had been cut and generators are being used at Sandy Beach Resort.
However, Mr Stavenow says he is more concerned about Cyclone Wilma's impact on communities, as crops including banana do not survive such storms.