China's Antitrust Law treats all business entities fairly and is strict in punishing monopolistic practices, a senior official said Wednesday.

The official response was made amid concerns over a series of anti-monopoly investigations into top global brands such as Microsoft, Audi, BMW and Mercedes-Benz over the past two months. Some critics suggested China is improperly using its anti-monopoly law against foreign firms.

"Some of the NDRC monopoly investigations involve overseas multinationals, but that does not mean that we are targeting them, " said Xu Kunlin, head of the anti-monopoly bureau under the National Development and Reform Commission (NDRC), the nation's top economic planning body.

"As a law-enforcement agency, we treat local and overseas companies equally to ensure justice for all. This is the spirit of the Chinese Antitrust Law, and the principle we always adhere to during law enforcement."

The nation's enforcement of anti-monopoly law has nothing to do with the ownership of the company, the NDRC's probes cover state-owned enterprises, private firms, and foreign-funded companies in wide-ranging sectors, he said during an interview with Xinhua Wednesday.

On Tuesday, fines worth more than 110 million yuan (17.8 million US dollars) were announced for 23 property insurers and one insurance association in east China's Zhejiang Province after evidence of price-fixing was found, according to the NDRC.

The nation's Antitrust Law was enacted in 2008. Xu said the purpose of the law is to prevent and stop monopolistic behaviors, ensure fair market competition, improve efficiency in the economy, and protect public interests.

The nation's supervision over monopolistic behaviors are strict and punishments severe. The Antitrust Law states that businesses with monopolistic behavior will be fined 1 percent to 10 percent of their annual sales revenues.

Punishments vary depending on the nature, severity, and endurance of the violations, Xu said.

"Based on the cases over the past few years, the overall penalties for monopolistic behaviors are not weak. Some companies were punished with fines of 6 percent of their annual sales," he said.

Until the most recent cases, the NDRC itself has launched anti-monopoly investigations into domestic and overseas LCD manufacturers, milk formula makers, pharmaceutical factories and liquor makers.

Last month, the NDRC handed down total fines of 1.24 billion yuan to 12 Japanese auto parts suppliers over price monopoly.