The US and the European Union are pushing China to soften or drop plans for compulsory certification of a range of technology products, as foreign IT companies warn that Beijing's regulatory requirements are pushing them out of the market.

The complaints come after Google's announcement last month that it was reviewing the feasibility of operations in China, saying it had been attacked by hackers based there. This highlights a broadening conflict between the Chinese government and foreign business over information security and intellectual property.

Rules set to take effect on May 1 will exclude suppliers of encryption-related products such as firewalls, secure routers or smartcards from government tenders unless they undergo testing and certification to meet Chinese standards. In some cases this will require submitting software source codes and other confidential information.