Thousands of workers plan to stage a demonstration on Friday in Timika, Papua, the province where the mine is located, to demand the government makes "a wise decision" regarding their situation, Solossa said.
"If they aren't careful, this has and will impact (Freeport operations), both for workers as immediate beneficiaries and the broader community as recipients of benefits from Freeport's presence."
Solossa added further action would be considered following the demonstration on Friday.
When asked about the stoppage, Freeport Indonesia spokesman Riza Pratama referred to the domestic smelter strike, and told Reuters that Grasberg's production was now being "managed to supply PT Smelting when their operations return to normal."
He noted Freeport did not have any plan to announce a force majeure yet.
"We are continuing to cooperate (with the government) so that our exports of concentrate can return to normal," Pratama said.
Freeport estimated in January that sales of copper from Grasberg would reach 1.3 billion pounds in 2017, up from 1.05 billion pounds in 2016, assuming operations were normal.