Vera Jourova, who is also the commission's vice president, made the comments after talks on Monday with Chinese counterparts including Vice Premier Zhang Guoqing in the second "High-level Digital Dialogue" between the two sides.

Among the concerns Jourova said she had heard about from European businesses in China was the "unpredictability of the decisions and interpretation of the laws by the regulators".

Beijing has implemented expansive new regulations recently, covering cybersecurity, counterespionage and data management, citing the need to shore up national security measures.

But the new regulations have worried some foreign firms, unsure of how their enforcement will affect their business operations in the world's second-largest economy.

"First thing is the not very clear wording of the laws, especially missing definitions of, for instance, what is 'important data', and what... the companies could be confronted with when transferring the data outside," Jourova told reporters.

Jourova also criticised the "lengthy procedures" foreign firms must undergo to conduct business in the country.

"I think it's 45 days for one process -- it lasts very often a much longer time," she said.

"Nobody is criticising the Chinese laws, we just want them to be clear and relatively easy to comply with."

The EU official and Czech politician's visit to Beijing comes just days after Brussels announced a probe into Chinese subsidies for electric vehicles, which it said had resulted in unfair competition.

China warned that the investigation would have a negative impact on its trade relations with the bloc, accusing it of "naked protectionism".