Freeport Indonesia's labour union may extend its strike at the Grasberg copper mine beyond one month, since talks with management were deadlocked, union official Juli Parorrongan told Reuters on Friday.

The union earlier said it planned not to continue with a tripartite mediation involving the government, and is seeking to discuss the matter directly with the company.

We didn't reach agreement with the management, Parorrongan said. We stated not to continue the mediation and seek a bipartisan with (Freeport chairman) James Moffett.

The strike continues until we reach agreement -- it is possible to extend it beyond a month, he added. No more mediation.

Earlier on Friday, a Freeport spokesman said in a text message that management respected the mediation process to find a solution to settle the dispute. He declined to comment on production.

Government officials, the union and Freeport, have been engaged in three days of mediation talks in Jakarta this week.

The union, which plans a month-long strike that started last week, says Freeport Indonesia's total workforce was 23,000 people, and that more than 12,000 of these were union members and striking.

The union is pushing for higher pay for workers, since it says other Freeport workers around the world get paid 10 times as much. The strike may also have been spurred by recent record prices for gold , given that Grasberg also has the world's biggest gold reserves.

Parorrangan said the union had offered to lower its demands from $17.5 per hour to $12.5-$10 per hour, but Freeport management had insisted on a 22 percent phased wage increase.

Freeport Indonesia mine workers' current rate is $1.50 to $3 per hour.

We can lower our demand to an ideal level, with note that management increases the offer, he said.

Documents seen by Reuters showed the lowest pay for striking workers at Grasberg is 3.7 million rupiah ($422) a month, with the union pushing for a rise to 27.2 million a month, plus higher education benefits.

On Wednesday, Freeport Indonesia said the strike at its Grasberg operation had limited mining, processing and shipping of concentrate at the world's third-biggest copper mine.

A day earlier, parent company Freeport-McMoRan Copper & Gold Inc's CEO Richard Adkerson said production at the mine had slowed significantly.

Sources told Reuters on Friday that contractors at the mine had restarted limited production, but not enough to ship the ore. Striking port workers also hamper shipment.

The copper market largely shrugged off supply disruptions at both Grasberg and a Freeport mine in Peru, hitting its lowest in more than a year amid a bleak outlook for the global economy.

Three-month copper on the London Metal Exchange traded at $7,290 a tonne at 0711 GMT, versus $7,674 at Thursday's close.