Creative Technology, a maker of portable media players, is suing Apple Computer  and has filed a complaint with the US International Trade Commission accusing the iPod maker of infringing on one of Creative's patents.

The Singapore-based company alleged in both complaints that Apple was violating its patent on a navigation system and method for organizing and accessing music on portable players.

Creative has dubbed the patent, the "Zen patent," after its brand-name Zen media players.

In the lawsuit filed in US District Court in San Francisco, Creative sought an injunction and unspecified damages. In its complaint with the trade commission, Creative asked the federal organisation to launch a patent violation investigation and force Apple to stop selling the iPod.

Representatives with Apple did not immediately respond to requests for comment.

According to the trade complaint, Creative was granted the so-called Zen patent in August 2005 after applying for it in January 2001.

The company unveiled the navigation system in a prototype mobile music player called the NOMAD Jukebox in January 2000 and has since used it in its NOMAD and Zen products.

In early 2001, representatives of Apple and Creative, including Apple CEO Steve Jobs, met to discuss ways they could work together, the complaint stated. Apple requested to license Creative's technology and also suggested it could invest in a potential spinoff of Creative's music player business, but Creative declined both proposals, according to Creative's complaint.

Then in October 2001, Apple launched its iPod - the iconic gadget that now dominates the portable media player market.

Apple's US market share was more than 72 per cent in 2005, while rivals such as Creative, were in the single-digit range, according to The NPD Group market research firm.