US Commerce Secretary Gary Locke said on Tuesday that China must adopt stricter copyright and trademark rules, while boosting penalties for intellectual property theft.
Locke, speaking at an intellectual property forum in the southern Chinese city of Guangzhou, also said the manufacturing powerhouse should focus on creating more "homegrown entrepreneurs."
China had made efforts to tackle what has become a thorny issue between the two trading partners, and officials inked agreements over the past year to beef up enforcement, the US commerce chief said.
"But despite these steps, American companies in fields as diverse as technology, entertainment and pharmaceuticals still lose billions every year in China from intellectual property theft," Locke said in prepared remarks supplied to AFP.
"In short, much more needs to be done."
Locke said US officials continue to receive reports of lax enforcement in Guangzhou and "occasional aggressive" efforts to clamp down on trademark infringement in Shenzhen, a city of 14 million near Hong Kong.
Guangzhou and Shenzhen are major manufacturing hubs in China's southern Guangdong province, which is home to more than 100,000 factories.
Locke's four-day visit to China ends Thursday.