NAVAREAS are the geographic areas in which various governments are responsible for navigation and weather warnings.
NAVAREAs are mentioned in International Maritime Organization Assembly Resolution A.706(17) adopted 6 November 1991.
The International Hydrographic Organization publication S-53 has a document entitled "Worldwide Navigational Warnings Service - Guidance Document" which is related to NAVAREAs. See http://www.iho.int/PUBLICATIONS/download.htm