Cyclone Gita was earlier upgraded to a category five - the highest possible.
The office's director, Anare Leweniqila, said damage assessments were on-going, but so far there were no reports of casualties or injuries on Ono-i-Lau.
"We have only received reports of three completely destroyed houses and we are just working around trying to ascertain the nature of these structures."
Mr Leweniqila said it was unclear if the homes were Fijian bures, made of corrugated iron or wood.
