New Caledonia is a dependent territory of France. If your passport describes you as a British Citizen you do not need a visa to enter New Caledonia. Other British passport holders should check the current entry requirements with the French Foreign Ministry. If you wish to remain in New Caledonia for more than three months, you should apply at the local Haut Commissariat or French Consulate for the necessary residence and work permits.
Your passport should be valid for the proposed duration of your stay. No additional period of validity beyond this is required.
The French authorities have confirmed they will accept British passports extended by 12 months by British Embassies and Consulates under additional measures put in place in mid-2014.
Yellow fever vaccination is required for travellers arriving from countries with risk of yellow fever transmission.
EU regulations regarding employment and right of abode do not apply to New Caledonia. British nationals have no right to work or to extend their stay beyond the initial three months without special authorisation from the local authorities.