Some people had moved to evacuation sites as heavy rainfall flooded their homes.
Others barricaded themselves in as authorities issued a red alert in the capital, Port Vila and some other regions, meaning people should not leave their homes unless absolutely necessary.
The cyclone forced businesses and schools to close and airlines to cancel flights.
Brenda Williams, a spokesman for Vanuatu’s National Disaster Management Office, said Cyclone Judy was carrying destructive winds of about 150 kilometers per hour (93 miles per hour) with gusts of up to 200 km/h (124 mph).
Williams said the calming eye of the tropical cyclone had passed over the capital Wednesday morning and they began to experience strong winds again as the tail moved through.
She said the center and southern islands were lining up to be hit and were still waiting for damage reports from many places.
Shadrack Welegtabit, a political adviser to the climate change minister, said people had been warned of the approaching cyclone earlier this week and had been preparing by stocking up on fresh drinking water and food and by strengthening the exteriors of their homes.
“It is still too early to estimate the damage; we’re still in the middle of it,” he said. “The other half is coming.”
Located in eastern Australia and northern New Zealand, Vanuatu has a population of approximately 300,000.