The head of a commission supervising state-owned companies in Shanghai has joined more than 50 people detained in the city's snowballing corruption scandal, government sources said on Monday.

Ling Baoheng, director of the city government's Assets Supervision and Administration Commission, was detained in Shanghai's pension corruption scandal. [file photo]

Ling Baoheng, director of the city government's Assets Supervision and Administration Commission, was detained at the weekend as Chinese President Hu Jintao pledged publicly to clean up government.

Also held was one of Ling's deputies, Wu Hongmei, two government sources told Reuters. A city government spokesman said he had not heard of the detentions, while an official at Ling's offices said nobody there could comment.

Beijing has sent more than 100 anti-corruption investigators to Shanghai to investigate money reportedly siphoned off from the city's 10 billion yuan ($1.25 billion) social security fund for illicit loans and investments.

Hu appealed on Sunday to the party's 70 million members to show solidarity. Later in the day, Hu attended a meeting of the International Association of Anti-Corruption Authorities.

"We are stepping up efforts to improve the rule of law and a culture for clean and honest government, and strengthen the checks and supervision on power," Hu told about 900 delegates.

Alarmed by chronic corruption and social unrest, Hu is steering the party towards reforms that would make officials more accountable.

As head of Shanghai's state assets commission, Ling oversaw the running of some of China's biggest firms worth billions of dollars. One was Shanghai Electric Group, China's largest power gear maker, several officials of which have been implicated in the scandal.

The investigation has jolted the city's red-hot property market, by threatening to expose illicit land speculation. But it has not damaged overall business confidence -- Shanghai's stock market hit a five-year high last week.