Quality watchdogs have prevented criminals from making billions of yuan from IPR violations, largely thanks to tighter links with police. Yet experts warn that many obstacles still remain in China's fight against fakes.

The General Administration of Quality Supervision, Inspection and Quarantine said it has solved cases worth a combined 12.3 billion yuan ($2 billion) in the past two years. Criminals had infringed on intellectual property rights or were involved in the manufacture and sale of counterfeit goods.

"We've intensified cooperation with public security forces over the past two years," Yan Fengmin, director of law enforcement and supervision at the administration, said at a news conference.

The agency dealt with 1,690 major cases in 2011 and in 2012 that figure rose a further 38.9 percent to 2,347.

Branches of the administration nationwide handed 1,716 cases involving fake or substandard products to police in 2012, up 44 percent from the previous year, Yan said.

The administration also discovered new problems, such as Chinese-made alcohol being passed off as brand-name imports.

In a joint operation last year, quality officials and police in Foshan, Guangdong province, detained three people suspected of faking famous brands, including Hennessy. Authorities confiscated 37,000 fake labels.

"Success in handling these cases has shown intensified cooperation is crucial between quality inspection authorities and public security forces," Yan said.

Cooperation with public security forces can help quality inspection authorities better enforce the law, said Dong Jinshi, executive vice-president of the International Food Packaging Association and an expert in food safety.

"Quality supervision and inspection administrations have only limited power and failed to check illegal activities in counterfeiting or substandard products effectively in some cases," he said. "Cooperating with public security forces will greatly facilitate law enforcement."

Despite progress, significant challenges remain, according to Gao Feng, deputy director of the Ministry of Public Security's economic crime department.

"After years of effort, the increasing number of such violations has shown they have not been effectively addressed yet," he said. "They are still rampant and public in some places.

Yan, at the General Administration of Quality Supervision, Inspection and Quarantine, agreed, and added: "In some places, protectionism disrupts law enforcement."

For example, officials in some places order quality inspection authorities to stay away from enterprises for 15 to 25 days a month, he said.

"Such a phenomenon is common," he said, and as a result, quality problems of regional products remain unaddressed.

Local interests involved in such illegal practices have made law enforcement difficult, Dong said.

"Things become even thornier when law enforcement officers are also involved in the illegal interests," he said.

Jin Zhu contributed to this story.