In Bua, some people had to flee as their houses disintegrated in the wind.
In Koro, destructive winds and heavy rain are being felt in Nasau Village and people have been relocated to two evacuation centres.
Panapasa Nayabakoro, who lives in Koro, said 32 people are sheltering at the Nasau Health Centre and the rest are in a school. He said most of their houses are flooded and some were houses blown away.
A teacher at Nacamaki District School in Koro, Ilisabeta Daurewa, said they are experiencing damaging winds and several kitchen sheds in the village have been blown away.
She said more than 100 people are taking shelter in six classrooms at the school.
MIL-Evening Report: Fiji declares state of disaster as TC Yasa wreaks havoc in Vanua Levu foreignaffairs.co.nz - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from foreignaffairs.co.nz Daily Mail and Mail on Sunday newspapers.
Cyclone Yasa has been downgraded to a category 4 storm but is still packing winds of at least 195km/hr with gusts of 275km/hr.
Fallen trees block Transinsular Road, near Lomaloma Village as Cyclone Yasa makes landfall in Fiji.
Photo: Facebook / Fijian Government
Tonga has now issued a cyclone warning as forecasts show it tracking close to the islands over the weekend.
Many houses in Fiji s Vanua Levu have been destroyed, some families sheltered under beds and tables in their houses and others in cane plantations, as Cyclone Yasa wreaked havoc in many parts of the Northern Division,
Fiji Village reports