Oma has moved closer to Santo over the past three hours and is currently travelling in a southeasterly direction with winds of 95 km/hr at its centre and the potential for gusts of 130km/hr.
At 2pm NZT on Thursday TC Oma was 145km west northwest of Santo.
Penama and Malampa Provinces have had their alert levels raised and are warned to prepare for damaging high winds, heavy rain, flash flooding and phenomenal sea swells.
Islands in Torba and Sanma Provinces of Vanuatu have so far been the most affected by the cyclone which remains a Category 2 system.
Shefa Province is on yellow alert.