(Reuters) - Chinese solar companies may ask Beijing to launch an anti-dumping and subsidy probe into imports of U.S. polysilicon, raw material used to make solar cells, into the mainland, a top official of China's solar industry association said on Tuesday.

China has been suffering from an overcapacity in polysilicon following a spate of investment in the sector after polysilicon prices peaked four years ago.

"Now members of the alliance are all strongly urging us to file a petition," Wang Bohua, chief secretary of the China Photovoltaic Industry Alliance, told Reuters.

He said the alliance has no timetable set for the filing of the petition with China's commerce ministry.

The alliance groups top solar firms such as polysilicon manufacturer GCL Poly Energy Holdings and polysilicon and solar panel makers such as Suntech Power Holdings, Yingli Green Energy that account for a combined 70 percent of China's polysilicon production and more than half of the country's solar panel production.

Wang's remarks came after a U.S. government decision earlier this month to investigate sales of Chinese-made solar panels -- which convert sunlight into electricity -- in the United States.

The probe was a result of a petition filed by American solar companies which sought to impose anti-dumping duties on Chinese-made solar products, which they say unfairly undercut prices and destroy thousands of American jobs.

In a statement posted on its website, the China Photovoltaic Industry Alliance said the volume of U.S. polysilicon imports into China had soared in the last two years after American polysilicon companies pushed down their product prices.

The sale of polysilicon at a discount to China has "encroached on China's polysilicon business, forcing companies to cut or halt production, and resulting in bankruptcies, and job losses," said the alliance.

China's polysilicon imports from the United States is expected to hit 60,000 tonnes this year, up from 47,500 tonnes in 2010 and 20,000 tonnes a year earlier, the statement said.

The alliance cited an unidentified Chinese province where about 19 polysilicon companies were forced to shut down, resulting in the layoff of up to 2,000 people.

The alliance also said the U.S. polysilicon companies were enjoying "substantial economic benefits" and receiving "hundreds of millions of dollars in government subsidies," on top of perks such as cheap electricity.