Hundreds of people have evacuated from their homes in Tonga as severe tropical cyclone Ula slammed into the tiny Pacific kingdom.

There are no reported casualties as Prime Minister Akilisi Pohiva declared a state of emergency before the storm hit “in order to prevent or minimise the loss of human life, illness or injury”.

The northern island of Vava’u took the brunt of the category three cyclone which was packing winds up to 150 kilometres per hour.

“We are very happy that there are no casualties, police checked with hospitals and town officers to confirm that,” the chairman of the National Emergency Management Office, Siaosi Sovaleni, told a press conference.

Cyclone #Ula, north of Tonga & nearing the International Date Line en route toward #Fiji. https://t.co/Wxm9RJ9Fns pic.twitter.com/U32zxKakXl

— UW-Madison CIMSS (@UWCIMSS) January 2, 2016

“We had 11 evacuation centres, over 390 people were relocated to these evacuation centres.”

Ula formed early on Thursday in the South Pacific between Tuvalu and Samoa and was initially expected to remain a category one storm as it tracked west-south-westerly.

However, it intensified to category two late on Thursday then to category three as it approached Tonga.

The storm brought down trees, damaged crops, and the main airport was closed to domestic flights.

The director of the Tonga meteorological office, Ofa Fa’anunu, said it was fortunate there was little moisture around which would have intensified the severity of the storm.

“On another day it would probably have become a (maximum) category five,” he said.

“If the moisture had been present it would have been the right ingredients for development into a much stronger system.”

The official Tropical Cyclone Warning Centre said in an advisory that Ula had “very destructive winds” with “very high to phenomenal seas” causing flooding in low-lying areas.

The hurricane warning for Vava’u was downgraded to a storm warning early on Saturday afternoon.

The tropical cyclone warnings for other island groups in Tonga were also downgraded.

The storm is expected to weaken Sunday as it heads towards Fiji.

But cyclone warnings remain in place in Tonga and Fiji’s National Disaster Management Office issued a strong wind and heavy rain warning ahead of Ula’s approach.

In January 2014, Tonga was hit by Cyclone Ian which left one person dead, 4,000 homeless and destroyed crops on outlying islands.

– ABC/Weatherzone