That figure has been given by the Civil Security organisation, which has gradually extended its extreme fire risk warning to now nearly all of New Caledonia, including the islands of Ouvea and Belep.
With winds still strong, there is no immediate relief in sight.
The authorities say at the same time last year just under five square kilometres had been burnt.
A territory-wide fire ban will remain in force until 15 December.
The ban exempts the use of fire for cooking in domestic situations.
New Caledonia regularly suffers drought conditions and experiences extensive bushfires.