Thousands of Tonga residents are facing a long wait for power and other services to be restored after Cyclone Gita tore through the Pacific nation.

More details emerged on Wednesday about the damage caused by the cyclone after it hit the main island on Monday night just south of the capital, Nuku'alofa.

The cyclone destroyed homes, churches and even the nation's historic Parliament House. There have been no confirmed deaths from the storm, although Tongan police said three people had suffered major injuries and another 30 suffered minor injuries.

Police said an officer had been injured while trying to help a family evacuate and remained in stable condition in a local hospital.

Most of the main island remains without power.

Cyclone Gita cleared away from Tonga on Tuesday, still packing winds of around 210 kilometres per hour with significantly higher gusts.

The system remains well organised because the eye of the storm has not made landfall throughout its passage so has maintained a constant supply of warm water.

The next few days will see the outer bands of the storm give a glancing blow the southern Islands of Fiji.

Gita will then move to the south of New Caledonia, and as it makes its way into cooler waters, it will steadily weakening on its way towards New Zealand.

It will be a much weaker system at this stage. There will be a spell of very wet and windy weather around the middle of next week, as the remnants of the storm punch through central parts of the country.