Chinese buyers of primary aluminum are reluctant to book imports for the second quarter as they hold limited cash and as falling premiums prompt them to postpone purchases, traders and industry sources said.

While China is the world's top producer of aluminum, some end users buy the metal abroad under a rule that allows them to import duty free as long as products made from the cargoes are shipped overseas.

Imports usually pick up after the weeklong Spring Festival holidays, which this year came in February, but buying has been weaker than expected this month, sources said.

Reduced buying will likely pile more pressure on premiums for primary aluminum ingots in Asia.

Premiums, the surcharge paid by buyers on top of the London Metal Exchange cash price to obtain prompt delivery, have fallen in the global market in the first quarter from record highs, with some analysts predicting further drops.

"Demand from clients [in China] for the second quarter is weaker than we had expected," said a trader at a global producer of primary aluminum, declining to be identified as he was not authorized to speak to the media.

"The biggest problem is that the market [premium] is falling. People don't want to commit now."

Factories still appear to have limited cash to buy aluminum despite recent measures by China's central government to boost liquidity, traders said.

An executive at a manufacturer of semi-finished aluminum products in South China's Guangdong Province said a weak Chinese property market had reduced cash at factories that produce aluminum profiles, used in the construction sector.