More than 5,000 people were sheltering at evacuation centers in Fiji's northern island of Vanua Levu on Monday as Cyclone Tomas approached.

The Nadi Weather Center said on Monday the cyclone had intensified overnight and is now a Category 4 system.

At midday on Monday, the storm was 185 km/h north-east of Labasa and 390 km north-east of Suva with winds of up to 175 km/h.

The cyclone caused chaotic seas that have already claimed one life. Fiji police confirmed on Monday that a 31-year old woman had died after huge waves swept her off a beach in Vanua Levu.

More than 100 evacuation centers have been set up throughout Fiji, and police, military, fire services and the Red Cross were scrambling to get the message out.

More evacuation centers were still getting set up as category four Cyclone Tomas on Monday struck Fiji's second-biggest island, Vanua Levu, slowly tracking south.

The cyclone was slowly moving south and was expected to affect all of Fiji through Tuesday. Major evacuations have been planned.

Fiji's capital Suva was battened down on Monday as the national weather office forecast one of the strongest ever tropical cyclone to hit the island nation in almost 40 years.

Fiji's 22,000 civil service was told to stay home and schools throughout the Pacific island country closed as the category 4 tropical cyclone intensified in strength.

The National Disaster Council (DISMAC), activated last Friday, has been working around the clock to advise people to prepare for cyclone Tomas.

DISMAC has warned people on the outer islands located on the path of the cyclone, especially those on the coast to move to higher grounds because of expected floods.

Flooding to low lying areas due to associated heavy rain, including sea flooding of low lying coastal areas from storm surges, according to the Weather office.

Reports reaching DISMAC headquarters in Suva confirmed that strong winds have destroyed seven homes on Qamea Island. The island is off Taveuni on the northern tip of Vanua Levu.

Strong winds were battering Vanua Levu at lunchtime on Monday, with some houses in remote coastal areas losing roofs and some flooded by strong sea swells. Parts of the island are without electricity. Most schools in the northern division have been turned into evacuation centers.

Fiji's permanent secretary for information Neumi Leweni said about 100 army and police personnel are on stand-by in Vanua Levu.

A nationwide curfew was lifted on Monday morning to allow people to buy emergency supplies. It will take effect again between 08:00 p.m. Monday until 07:00 a.m. Tuesday.

Tourism Fiji said Air New Zealand and V-Australia had cancelled all Fiji services until further notice and Air Pacific said it would postpone flights to Fiji ex-Auckland, Brisbane and Sydney until Tuesday.

Cyclone Tomas has already hit Wallis and Futuna to the north of Fiji on Monday, causing damage to some houses and crops.