The cyclone, with winds gusting up to 265 km/h close to its centre, is affecting Vanuatu's Torba, Sanma and Malampa provinces.
Disaster authorities in Vanuatu said people and supplies were standing by ready to be deployed to cyclone-hit areas as soon as possible.
RNZI reports the worst-hit Torres Islands, where houses have been toppled and food crops destroyed, continue to experience winds gusting over 200 km/h.
The director of the disaster management office, Shadrack Welegtabit, said continued stormy weather was hampering the response effort.