"It's not a sensible move for the US government to file such complaint," said Tian Lipu, commissioner of the Intellectual Property Office, at a national meeting of IPR officials in Nanchang, capital of east China's Jiangxi Province.

By doing so, the United States had ignored the Chinese government's immense efforts and great achievements in strengthening IPR protection and tightening enforcement of its copyright laws, Tian said.

"Such efforts are continuous and China has never slackened," he told Xinhua.

Tian cited a new judicial interpretation issued by the Supreme People's Court last week that lowered the threshold for prosecuting manufacturers and vendors of counterfeit intellectual property products.

The new rules state that anyone who manufactures 500 or more counterfeit copies (discs) of computer software, music, movies, TV shows and other audio-video products can be prosecuted and faces a prison term of up to three years.

They replace the 2004 rules whose net only extended to those who produced 1,000 pirated discs.

"It's a practical move and indicates China's determination to fight piracy," said Tian. "But the United States has filed a WTO complaint right when China is forging ahead with its IPR protection efforts."

IPR protection was an international issue and needed international cooperation, he said. "To do a better job in combating piracy, we need dialogue and cooperation, not confrontation and condemnation."

Tian said he hoped the United States would work with China in exploring ways to make IPR protection more effective and further tighten enforcement of copyright laws.

IPR protection, Tian said, also served China's goal for overall development. "Whether the Americans take us to the WTO or not won't affect the Chinese government's determination to protect IPR and combat copyright piracy."

The US government announced on Monday it was filing two new trade cases against China over "copyright piracy and restrictions on the sale of American movies, music and books there".

On Tuesday, China expressed its great regret and strong dissatisfaction at the US decision to file WTO cases against China over intellectual property rights and access to the Chinese publication market.

"The Chinese government has always been firm in IPR protection and its achievements are for everyone to see. China and the United States have also maintained sound communication and consultation on the access to the Chinese publication market," the Ministry of Commerce said in a statement.

The United States' action against China contradicted the consensus between Chinese and US leaders to bolster bilateral trade and economic relations and properly settle all trade disputes, it said.

Such a move would "seriously harm the existing Sino-US cooperative relations" and have "a negative impact on bilateral trade and economic relations", said the ministry's spokesman Wang Xinpei.

The Chinese government has not yet received a request for consultations from the United States, but will deliberate upon and actively respond to a formal request, said Wang.

Under WTO rules, if the parties to a trade dispute fail to iron out their differences within a 60-day consultation period, the complaining party may refer the matter to a WTO dispute settlement panel.