''As we are seeing in the United States, Europe's patience could wear thin if we do not see our dialogue with the Chinese authorities delivering more change when it comes to IPR (intellectual property rights) and other market issues,'' Peter Mandelson told reporters.
European companies have complained in the past that the European Commission is not as aggressive as the United States in tackling obstacles to exports or investment in countries, including the fast-growing, export powerhouse China.
In recent weeks, Washington has filed cases at the World Trade Organisation (WTO) against China, accusing Beijing of subsidising local industry and failing to prevent intellectual property theft.
At a news conference to announce the latest element of his plan to open up foreign markets for EU companies, Mandelson was asked if the bloc might join the United States on the IPR case.
''I do not rule out initiating or joining action at the World Trade Organisation if, in our view, China is failing to take its responsibilities seriously,'' he said.
Although China had made some progress, protection of intellectual property rights remained ''patchy and uneven,'' Mandelson said, adding EU companies lose an estimated 20 billion euros (.18 billion) a year because of Chinese trade barriers.
Conversely, Chinese officials have protested at what they consider unfair barriers to their exports to Europe which have been hit by anti-dumping duties, including leather shoes.
POOL KNOW-HOW ON THE GROUND Refering to the new chapter of his market-opening plan, Mandelson said it was time to pool the expertise of the Commission's trade specialists with those of European governments and business, especially in third countries.
''EU business relies on growing markets abroad to fuel economic growth and jobs at home,'' Mandelson said, suggesting the United States and big developing countries such as Brazil, Russia, India and Asia's economies could be in his focus.
European exporters are increasingly frustrated that countries outside the bloc are putting up barriers in the form of higher local taxes, excessive regulation or lax protection of intellectual property.
Wednesday's announcement, which has yet to be put to EU capitals, is part of Mandelson's more ''hard-headed'' plan to open up new markets which he outlined last year, including new trade deals with some of Asia's biggest economies.
Brussels also hopes to negotiate separately more access to China's markets.
The Commission said it did not intend to establish ''an EU trade policy militia'' with its pooled resources plan.
''We will keep our market open and are confident that our established trading partners like the U.S., or key emerging countries...will understand our concern to find fair rules in other markets around the world,'' it said in a statement.
Reuters PBB KP2101