The Frieda River project, a planned large open-cut mine with associated infrastructure in East Sepik, West Sepik and Sandaun provinces was first proposed decades ago.
However, the plans of Chinese-owned, Australian-incorporated company PanAust to build the mine just upstream of the Sepik River, the longest river on New Guinea, sparked concern among local communities.
Many locals are dependent on the river system for food, and it was feared that the mine's industrial footprint would cause permanent devastation, Radio New Zealand Pacific reported.
East Sepik's provincial legislature under the leadership of Governor Alan Bird has voted not to approve the project.