Workers at the world's largest gold and copper mine in Indonesia have promised to strike indefinitely until their demands are met.

Most of the workforce at the giant Freeport McMoRan Mine have been on strike for a month which they have extended for another 30 days.

They claim the company has tried intimidation to get them back to work, and has forced contractors back to the mine. These claims are impossible to verify as the company does not comment to the media.

Reporter: Karon Snowdon

Speaker: Juli Parorrongan, spokesman for the mine workers' union, the SPSI

Snowdon: The strike over better pay and a pension plan began on September the 15th. Eight thousand workers at the Grasberg Freeport mine walked off the job and have vowed to stay on strike indefinitely.

Parorongan: So tragically, the management is not building the solution or the resolve of this problem, but they build the conflict. And they prolong the conflict. Management of... have strongly indicated they are not wanting to answer or fulfil our demands.

Snowdon: The union says wages are among the lowest in the world at just $2.10 an hour for some. It wants that raised to $17.50 an hour plus a better pension plan.

Parorongan: The lowest paid is 2.10 dollar per hour. And so, we need this to be increased to 17.50 dollars per hour.

Snowdon: That's a big increase all in one go, isn't it?

Parorongan: Ya, that's a big increase but this company also has the biggest revenues, and so we're... our Indonesian salary is very very low, especially for the Freeport McMoran group. You can compare wtihin your country.

Snowdon: Juli Parorongan says its the first time the entire union workforce at Freeport has gone on strike. He accuses the company of using intimidation to force contractors back to work. Freeport management says it started negotiations last month for a new labour agreement in good faith and there's no legal basis for the strike. In a written statement Chairman James Moffett says he's committed to getting a fair agreement.

Moffett: In 2010, the contribution from Grasberg to the Government of Indonesia and the local community totalled more than $3.8 billion. We are committed to maintaining an attractive work environment for our employees and look forward to concluding the negotiations on a mutually agreed basis as soon as possible."

Snowdon: The company says the strike is costing 3 million pounds of copper and 5 thousand ounces of gold a day in lost production. It won't meet its forecast third quarter sales of over 900 million pounds of copper and over 400 thousand ounces of gold. Union spokesman Juli Parorongan says the Indonesian government needs to get involved and pressure the company, PT Freeport Indonesia or PTFI.

Parorongan: Because the PTFI management have already have out of laws.

Snowdon: Are you saying the management has broken the law?

Parorongan: Ya, that's right. They're already broken the law, especially for their employment law in Indonesia. But it will be very good if you can come to Indonesia and so you can see for yourself.

Snowdon: The Indonesian government doesn't allow journalists to visit Papua. The strike action appears to have a long time to run.

Parorongan: We will strike for longer and longer, until we have the good deal.