BEIJING (Reuters) - China defended its government-funded Confucius Institute programs on Friday after new questions were raised in the United States about their transparency and effect on academic freedom.

China says its Confucius Institutes around the world are established by universities voluntarily, and that such centers promote Chinese-language learning and academic and cultural exchange.

But the institutes have raised concerns that they threaten academic freedom, conduct surveillance of Chinese students abroad and promote the political aims of China's ruling Communist Party.

On Thursday, the U.S. House Committee on Foreign Affairs held a hearing on whether academic freedom is threatened by China's influence on U.S. universities, with the Confucius Institute receiving particular attention.

Chinese Foreign Ministry spokeswoman Hua Chunying said that all Confucius Institutes in the United States had been voluntarily applied for by U.S. universities.

"All class and cultural activities are open and transparent. The Chinese side has provided teachers and teaching materials assistance according to requests of the U.S. side. It has never interfered with academic freedom," she told a daily news briefing.

"We hope everybody can make joint efforts to reject prejudice and work together to better build these bridges of friendship and make them stronger."

At the Washington hearing, Congressman Chris Smith said he would ask the Government Accountability Office to review agreements of both satellite campuses for U.S. universities in China and of Confucius Institutes in the United States.

"I would like to know if those agreements are public, whether they compromise academic or other freedoms of faculty, students, and workers and whether Chinese teachers are allowed the freedom to worship as they please and teach about Tiananmen, Tibet, and Taiwan," Smith said.

In September, the University of Chicago said it would suspend negotiations to renew the Confucius Institute on the school's campus, citing comments in the media that were "incompatible with a continued equal partnership".

Despite tight government control over curriculum, many foreign universities have rushed to establish partnerships with China in an effort to improve access to the country's huge educational market. That has created unease about whether schools would be forced to sacrifice academic freedoms.

Xia Yeliang, a prominent Chinese professor and dissident who was fired from the elite Beijing University last year, has warned that academic exchanges with China carry hidden risks, such as visiting scholars who may be sent as spies.

(Reporting by Ben Blanchard and Michael Martina; Editing by Nick Macfie)