Apple has filed a lawsuit against Creative, alleging that maker of the Zen portable media players has infringed on four of its iPod patents.

Apple filed the action on the same day that Creative filed a patent suit in which it accused Apple of infringing on one of its patents concerning the iPod user interface.

The two companies have been in negotiations over Creative's patent which covers navigation by menus and organisation of music on a portable music player.

Creative was one of the first firms to make portable digital music players, but has a market share of less than 10 per cent in the US.

Apple controls approximately 77 per cent of the portable media player market.