Workers at Freeport McMoran Copper & Gold Inc's Indonesia unit delayed their return after a three month strike because 500 employees of sub contractors lack job security.

Union spokesman Mr Virgo Solossa said that the workers hope to resolve the dispute and start heading back to the Grasberg mine in the central highlands of Papua island, eastern Indonesia, on Tuesday.

Mr Solossa said that "It's likely that we will be back to work tomorrow as around 500 workers from several sub contractor companies still have issues that need to be settled first. Today we want to make sure that all contractors have no issues.”

The strike at the world's second largest copper mine shook labour relations in Southeast Asia's largest economy because it was a high profile attempt by workers to gain a larger share of the rewards in a booming economy.

The strike ended on December 14 with a deal under which Freeport agreed to a pay increase of roughly 40% for around 8,000 union members and to a framework for a better deal for roughly 15,000 other non-union workers and contractors.

Arizona-based Freeport earlier said it expected full operations at the Grasberg mine to resume in early 2012.

The union has not returned to work largely because of a dispute with contractor PT Kuala Pelabuhan Indonesia over possible sanctions on workers who took part in the strike. Last week KPI agreed to rehire about 700 workers who went on strike with no sanctions.

Monday's dispute appeared to be similar to the union's with KPI.

(Sourced from Thomson Reuters)