Indonesia's Mining Advocacy Network says new mining legislation being debated by parliament could mean Freeport McMoran's operations at the Grasberg mine in Papua are reviewed.
Officials say the new law, debated in Indonesia's parliament since February 2006, is due to be passed by the end of this year.
New mining regulations under the Act would shorten the period of mining contracts, which has made some overseas investors wary.
Siti Maimunah of Indonesia's Mining Advocacy Network says the new regulations would also provide for reviewing of old mining contracts, something which many Papuans have been calling for in relation to Freeport's operations in Timika.
"Debating in the parliament, looking at the possibility to reviewing the old contracts or permits, they must follow the new regulation. It will require them to have reviewing of the contract and things like that. I think this is the important step. But the companies don't like this."