Up to 1,500 striking workers at Freeport McMoRan Copper & Gold Inc.'s giant gold and copper mine in Indonesia's remote Papua province protested outside a government office on Thursday, urging authorities to help end a dispute over pay.

After mediation talks failed last week, union officials have urged parliament in Jakarta to intervene to resolve the dispute. The tripartite talks ended in deadlock last Friday between Indonesia's Manpower Ministry, the company and union officials.

Virgo Solossa, a union official, said a meeting may take place on Friday involving new parties such as local government officials and local parliament members.

We're waiting for an invite from the parliament here for a discussion hopefully on Friday, he said.

Freeport, home to the world's third-largest copper mine, has a total workforce of about 23,000, thousands of whom began a one-month strike on Sept. 15. The miners' union has lowered its pay rise demand to $12.50 to $37 an hour from $17.5 to $43 an hour, added Solossa.

That compares with $1.5 to $3 an hour currently.

A shipping worker from Freeport's Papua port said loading activities had eased as some of contract workers at the port had left. It was not immediately clear why they had left the area.

The strike has stirred concerns it may boost metal prices amid a global shortage. Freeport is the world's biggest publicly traded copper miner and its Grasberg facility has the world's largest recoverable reserves of copper and the largest gold reserves.

The estimated impact on production is about 3 million pounds of copper and 5,000 ounces of gold for each day of the work stoppage, according to Freeport. Last week, Chief Executive Officer Richard Adkerson said only that production had been slowed significantly.

Local subsidiary PT Freeport Indonesia said in a statement on Monday that it was working diligently and constructively to reach a new labor agreement.

The stoppage has also raised concerns over a broader push by workers for a greater share of profits in Indonesia, Southeast Asia's biggest economy. Pilots and supermarket staff have also recently gone on strike.