SYDNEY, Dec 14 (Reuters) - Low voter turnout at New Caledonia"s independence referendum, after a boycott by indigenous groups "weighs heavily" on the French territory"s self-determination process, election observers from the Pacific Islands Forum said on Tuesday. France declared the result of Sunday"s referendum showed 96.5% of those who voted opposed independence, compared to 57% in 2018 and 53% in 2020. However, only 43.9% of voters participated due to a boycott called by Kanak leaders after France declined to delay polling until next year to allow for a traditional mourning period for COVID-19 deaths. Pro-independence groups said they did not recognise the legitimacy of Sunday"s vote, the third and final referendum to be held under the 1998 Noumea Accord, a peace deal struck to end a decade of violence. read more Election observers from the Pacific Islands Forum, the region"s main inter-governmental group, said a significant proportion of voters, mainly independence supporters, had not voted in a stance made known before the referendum. "The spirit in which the referendum was conducted weighs heavily on the Noumea Accord and New Caledonia"s self-determination process," the group said in a statement. "Civic participation is an integral component of any democracy and critical to the interpretation and implications of Sunday"s poll." The observers, who are preparing a report on the election, were led by Fiji"s foreign minister Ratu Inoke Kubuabola, with the forum"s secretary general Henry Puna also travelling to New Caledonia. The group met with New Caledonia"s Congress president, Roch Wamytan, before he travelled to New York to raise concerns about the referendum at the United Nations on Thursday, and then to France. One of five island territories spanning the Indo-Pacific held by France, New Caledonia is the centrepiece of French President Emmanuel Macron"s plan to increase its influence in the Pacific. The nickel-rich territory is 20,000 km from France, with a population including 41% Melanesian (mostly Kanak) and 24% of European origin (mostly French). Sensitivities over colonization run high among New Caledonia"s neighbouring countries. read more