Apple has broken its silence in the face of growing anger from consumers about faults in its iPod Nano music player.

Launched earlier this month the Nano is the replacement for the iPod Mini and is exceptionally small and light. But users have complained that the screens are very easy to scratch and crack, and have raised doubts about battery performance. 

Apple is claiming that the screen problems occurred with one particular batch of Nanos that suffered a manufacturing flaw affecting "less than one-tenth of one per cent" of its stock.

Phil Schiller, senior vice president of worldwide product marketing at Apple, said: "This is a real but minor issue involving a vendor quality problem in a small number of units.

"We have received very few calls from customers reporting this problem. We do not think this is a widespread issue."

Nanos from this batch will be replaced free of charge. Schiller insisted that the screens were made with the same material as the iPod Minis, about which Apple claims to have received no complaints.

Matthew Peterson, a Nano owner who set up a website to track complaints, said: "This was a real issue and most people tried to ignore it.

"I know a lot of people are going to complain that they still have to spend extra money on a case to prevent scratching. I guess I can handle using an iPod sock on my Nano knowing that I can look at my screen and show someone a picture. "