* Category three storm hits New Caledonia
* French nickel firm suspends mining, but keeps smelters going
* The cyclone alert was widened on Monday (Updates weakening forecast, adds nickel mining impact, quote)
By Charlotte Greenfield and Tom Westbrook
WELLINGTON/SYDNEY, April 10 (Reuters) - Cyclonic winds and heavy rain buffeted New Caledonia on Monday, prompting residents of the French South Pacific territory to seek shelter and halt mining of nickel, its most important export.
Cyclone Cook hit the main island at almost the same time as high tide, packing winds of up to 200 kph (124 mph), bringing down coconut trees to block roads and forcing residents to seek shelter indoors.
"Right now we are in the eye of the storm, it is calm, but before the wind was strong and the rain was heavy," David Sigal told Reuters as he sheltered in the town hall of Poindimie, about 50 km (31 miles) north of where the storm hit land.
Floods, and waves as tall as 10 metres (33 feet), were also forecast by weather authorities.
"The threat to New Caledonia is very serious," the meteorological service said in a cyclone alert.
The storm hit land late on Monday afternoon as a Category Three storm, said Virgil Cavarero, a forecaster at Meteo New Caledonia, below the destructive Category 4 predicted earlier, which would have been a level off the most dangerous wind speed.
Authorities widened their cyclone alert on Monday, however, warning residents nearly everywhere in the archipelago to seek shelter before evening.
Nickel group Societe Le Nickel, a subsidiary of French conglomerate Eramet ERMT.PA , has suspended mining at its five locations in New Caledonia, though smelting operations continue at a reduced level in the capital, Noumea, the firm said in a statement emailed to Reuters.
New Caledonia is one of the world's largest sources of nickel, and mining and metals processing plays a major role in its economy. Its two other main nickel producers, Glencore Plc GLEN.L and Vale VALE5.SA , were not immediately available for comment, however.
Cyclone Cook, tracking southward, is predicted to pass within 50 km (31 miles) of Noumea during the night. Strong winds, heavy rain and rain are forecast to batter the 400-km (250 mile) length of the main island and smaller islands nearby.
As a precautionary measure against the cyclone, none of the roughly 100 guests staying at the packed hotel Le Lagon, in south Noumea, will be allowed to leave in the evening, said manager Emilie Coste.
After passing through New Caledonia, Cyclone Cook is forecast to gather strength and hit flood-soaked New Zealand, as the threat from recent Cyclone Debbie dissipates.