CHINA has warned United States President Barack Obama not to meet the Dalai Lama and threatened diplomatic reprisals over US arms sales to Taiwan, opening a new front in an escalating feud between the world's top powers.

Beijing's tough rhetoric piled pressure on a crucial relationship already severely strained over Google's threat to halt operations in China, which sparked a row over Internet freedom, and a host of trade and currency disputes.

China and the United States are working together on several pressing international disputes, including fraught negotiations aiming to curb the nuclear ambitions of North Korea and Iran.

But Beijing hinted today that it may no longer be willing to play by US rules on such key foreign policy issues, and blamed Washington for any negative consequences.

"China-US relations, in important international and regional issues, will inevitably be influenced (by the Taiwan deal) and the responsibility completely lies with the United States,'' foreign ministry spokesman Ma Zhaoxu said.

Ma also called on US companies selling arms to Taiwan - corporate giants like Boeing, Lockheed Martin and Raytheon - to back away from the arms deal, after earlier warning that Beijing could impose sanctions.

China is now the largest holder of US government debt, and some analysts have suggested that its economic clout has emboldened leaders of the world's most populous nation to take on Washington in a more forceful way.

The sanctions threat was indeed a new step by Beijing, which has always strongly opposed US arms sales to Taiwan and also cut off military and security contacts with Washington in retaliation for the deal.

Washington last week approved a package of Patriot missiles, Black Hawk helicopters and other military hardware totalling $US6.4 billion ($7.18 billion) for Taiwan, which China views as part of its territory awaiting reunification.