The small islands of the Lau group have been warned to expect destructive storm force winds of up to 155 kilometres an hour over the next few hours.
At its centre the category three system is producing average winds of 150 kilometres an hour and gusts of more than 205 kilometres an hour.
Planner for the Eastern Division, Eliki Masa, says there have been no reports of significant damage although some trees have been damaged.
Mr Masa says the Lau group has been well prepared.
"The committee within every village, the preparedness committee, have been alerted to move all the community to a well-structured building. As far as the building is concerned. Some of them have moved to the churches. Some of them have been moved to the community hall. Some of them have moved to a well secured concrete building especially for them to take shelter in the next coming 12 hours, especially the night."
liki Masa says people on Ono-I-Lau, which is expected to feel the worst of the storm, have been preparing to move to schools that are located on higher ground.
Ula is moving slowly away from Ono-I-Lau but also has the potential to strengthen further.