Apple is being sued by a small US firm for allegedly infringing on a patent covering web browsing technology.

EMG Technology filed suit at the US District Court in Tyler, Texas over Apple's use of a system that shrinks pages to fit smaller screens, which it says infringes US Patent 7,441,196 that was awarded to EMG on 21 October.

Stanley Gibson, a partner with Los Angeles law firm Jeffer, Mangels, Butler & Marmaro who is acting for EMG, said: "The claims cover the display of internet content reformatted from HTML to XML on mobile devices - the industry standard currently displayed by the iPhone. Additional patent claims include the technology for manipulating a region of the screen for zooming and scrolling.

"Web sites are just beginning to develop their mobile sister sites for fast and easy navigation. For example, to access NBC on a computer the URL is NBC.com. For the mobile site on the iPhone, the URL would be m.NBC.com. The '196 patent covers the simplified interface of reformatted mobile content to provide optimum viewing and navigation with single touches on a small screen."

Gibson recently took part in a similar suit against Medtronic which was settled for $570m (£377m).

Apple is the only company named in the suit. "We have not looked at anything other than the iPhone," Gibson told Reuters. "That was the device that we looked at. Obviously, it's very popular."