The French government is to submit a request to Unesco to have the reefs and marine resources around New Caledonia protected as world heritage sites.
The bid will be made by the French environment minister before the end of January.
The proposed reserve is to cover more than 15,000 square kilometres including a reef 1,600 kilometers long.
A marine scientist in Noumea says 350 types of coral have been identified in New Caledoania of the 700 varieties known worldwide.
The proposal for the reserve was tabled at a conference in Hanoi four years ago and could be realised by 2008.