Yunus Saefulhak, minerals director at the country's energy and mineral resources ministry, scaled back his estimate last month of 91 million tonnes of input capacity at 37 operating smelters in 2021.

"After we evaluated, some are showing very slow progress," Saefulhalk told reporters. "If they can complete construction in 2022, we consider those as a bonus."

Indonesia has 11 of the 29 smelters already in operation, with annual input capacity of nearly 27 million tonnes.

The government also revised down its projection for bauxite smelters to nine, from 11 previously.

The government is pushing for domestic ore processing to add value to its exports.

Indonesia, a major exporter of nickel ore, is set to stop exports of raw nickel in January. Exports of other ore and concentrates will stop in 2022.

Overall, the government expects a total of 52 mineral processing plants in 2022 with total combined investment estimated at $20.39 billion.

(Reporting by Wilda Asmarini; Writing by Fransiska Nangoy; Editing by Clarence Fernandez and David Goodman)