China's top propaganda official on Monday urged the state-run Xinhua news agency to better serve the Communist Party and become a "world-class" multimedia organisation as it turned 80.

In a speech at the Great Hall of the People in central Beijing to mark the anniversary, Li Changchun -- number five in the party hierarchy -- urged Xinhua to play a stronger role in publicising government decisions.

The government wants to use Xinhua to project its voice globally as part of a major "soft power" push, and the news agency is due to expand its bureaus around the world from the current 162 to about 200 by 2020.

He pointed to a resolution made last month at a party plenum to expand government reach into cultural affairs -- widely seen as an effort to curb the expanding influence of the Internet, including the hugely popular Twitter-like microblogs.

"We hope Xinhua will serve the plenum... improve its capacity in guiding public opinion" and "do more to safeguard social stability", Li said in his speech to scores of diplomats and foreign media representatives.

"Xinhua has an important responsibility in spreading the resolution," Li said. "It is a top priority."

"Xinhua must speed up its integration with modern technologies and multimedia technologies to become a world class media organization," he added, urging the agency to offer "more vivid" reporting.

In recent years, the news agency -- flush with government funding -- has sought to expand its footprint overseas, and has set up an expansive website.

The agency currently employs 11,000 people, including 5,000 journalists, and produces news in eight languages including Chinese, English, French, Russian, Spanish, Arabic, Portuguese and Japanese.

In July 2010, Xinhua set up CNC World, a 24-hour television news station modelled on the American CNN and Britain's BBC, which aims to cover the news in about 100 countries.

Li Congjun, head of Xinhua and a member of the party's powerful central committee, said at the time of the launch that CNC "will offer an alternative source of information for the global audience, and aims to promote peace and development".

On Monday, he repeatedly stressed the loyalty of the agency to the party and its succession of leaders including Mao Zedong and Hu Jintao.

"We must fight for socialism with Chinese characteristics" and "foster a Marxist news concept", he said.

Xinhua was founded by the Communist Party on November 7, 1931, as the sole mouthpiece of the then youthful party, which was struggling to survive in the midst of civil war and political purges.

Now, though, with more than half a billion Internet users in China and over 200 million users of microblogging sites, authorities have sought to master new technologies to beef up their controls over traditional media outlets.

In an example of these efforts, nearly 40 companies, including e-commerce giant Alibaba, online portal Sina and search engine Baidu, attended a three-day seminar hosted by the State Internet Information Office, an online watchdog.

At the end of the government workshop on Saturday, the heads of these firms vowed to stop the "spread of harmful information" on the web.