Sarawak Tourism Board chief executive officer Gracie Geikie said the Mulu Caves, the state's prized tourism asset, would lose its appeal if efforts were not taken to improve the rural air transportation system.
"We have invested a lot to promote Mulu Caves as a tourism product. If the situation does not improve soon, we will continue to incur losses," she added.
Some three million tourists visited Sarawak last year.