European Union Trade Commissioner Peter Mandelson has made a fresh call for China to do more to improve market access and cut down on piracy.
He warned China would face a backlash in Europe unless it did more to "apply rather than circumvent the rules".
Mr Mandelson's comments came during a visit to Beijing for talks with his Chinese counterpart Bo Xilai.
European and US firms have long complained about the volume of pirated goods on sale in China.
Brussels and Washington have also clashed with Beijing over a number of trade issues in recent years, most recently accusing China of unfairly dumping clothing and shoe products on their markets.
This has led to both the US and European Union tightening import quotas, although China insisted it was merely able to produce goods more cheaply and was being unfairly victimised by Western protectionism.
"The more the Chinese door swings open and the world sees a responsible China playing by the rules, the more our citizens will be able to understand our shared interest in deepening our relationship," Mr Mandelson told students at Beijing's Renmin University.
He added that both the EU and China had to "commit to openness and resist protectionist pressures".
Despite a number of crackdowns by the Chinese government, counterfeit goods are still widely available in China, ranging from pirated movies to fake branded clothes and copied medicines.
The US government is also continuing to call on China to tackle piracy, with Washington warning earlier this week that it could take China to the World Trade Organisation over abuse of intellectual property rights.