China's top trade union federation has lambasted McDonald's, KFC and Pizza Hut for "underpaying" workers in Guangzhou.

Responding to media reports against the fast-food giants, a senior All China Federation of Trade Unions (ACFTU) official said: "No company should enjoy special privileges in China. Irrespective of how big or strong a company is or who owns it, no company should be allowed to have in-house rules that violate the country's law."

In an interview with China Central Television over the weekend, ACFTU security work department head Li Shouzhen said the federation would provide free legal help to the "underpaid workers".

Guangzhou-based New Express reported last week that the global fast-food chains were "violating labor laws" by underpaying part-time workers, most of who are college students. The newspaper's undercover probe, the report said, showed such workers were paid just 60 percent of the nominal wage and made to work overtime, too.

This year the government of Guangdong Province, of which Guangzhou is the capital, set the minimum wage for part-time workers at 7.5 yuan (97 cents) an hour. But McDonald's pays only 4 yuan (52 cents), KFC 4.7 yuan (61 cents) and Pizza Hut 5 yuan (65 cents) an hour, the investigation "revealed".

McDonald's and Yum! Brands Inc, which owns both KFC and Pizza Hut, however, have denied violating labor laws. Local labor authorities have already begun an investigation, and the result is expected tomorrow.

The ACFTU has informed its office in Guangdong to "get things clear as soon as possible", Li said.

"If the violations prove to be true, the federation will ask the companies to correct their wrongdoings," Li said. "If they refuse to do so, we will help the workers file a case against them."

With the help of the Ministry of Labor and Social Security, the ACFTU in May will launch a campaign against companies violating labor laws, including employment without proper labor contracts, failure to pay wages and underpayment.

Li urged foreign companies doing business in China to set up trade unions to settle disputes between employers and employees.

Editor: Yan