Plans to issue new European Union rules on patents for the software industry have hit a fresh obstacle, with a European parliament report urging changes to the law that would make it more difficult for many high-technology companies to register patents for their inventions.

The proposed amendments put parliament on a collision course with groups such as Nokia, Philips and Siemens. They could also spark a fierce battle with EU member states, who backed a more industry-friendly regime earlier this year.