China's importers of refined copper face a shortfall of about 30,000 tons this month and the next as a typhoon-hit Philippine smelter has delayed metal deliveries, supporting spot premiums near four-year highs, traders said Thursday.

Lower-than-expected arrivals may force importers to buy spot metal, in a move that would help support prices of the metal, which have fallen more than 10 percent this year.

Importers in China were told by trader Glencore Xstrata that deliveries of contracted refined copper from the PASAR plant in the Philippines would be delayed, two trading sources said, adding that the seller did not say when delivery would resume.

A spokesman for Glencore Xstrata did not immediately comment.

Another trader said PASAR had also selectively halted shipments to some customers in the region, for example in Thailand and Vietnam.

Glencore Xstrata last week confirmed that PASAR had suffered heavy structural damage from one of the world's biggest typhoons, which killed about 4,000 people and left more than 4 million homeless. The firm estimated a return to normal operations would take at least four to six weeks.

"[Glencore] did not say when the delayed shipments will arrive," said an importer waiting for PASAR metal bought by his firm, who declined to be identified because he was not authorized to speak to the media.