Apple's proud new generation of Intel-based Mac laptops may be facing yet another widespread problem, according to a website random-shutdowns.

The site, macbookrandomshutdown.com, was created by Matthew Swanson of Atlanta, Georgia, who found that his 2GHz MacBook began suddenly switching itself off a few weeks after purchase. "I started this site to discuss the issue. Is this happening to anyone else?" Swanson explained on the site.

Quite a few have, apparently. Since its launch about two weeks ago, the site has attracted dozens of posts, with shutdowns reported in India, Japan, Australia, the US and elsewhere. Users have also reported the problem on Apple's tech support forums and sites such as Mac Rumors.

An Australian user who took the laptop in for repairs said the problem didn't take long to recur. "I tested it in the store by opening three or four AVI movies I had on my hard drive, and what do you know? It shut down again!" he wrote.

Another user said Apple was replacing various parts of the system in an effort to track down the problem. "The Apple Store service department doesn't know what to do, but have agreed to swap the logic board, and replace the bezel, top case assembly and heat sink," he wrote.

So far Apple hasn't made any official acknowledgement of the issue.

Recently Apple has offered fixes for two issues widely experienced with the MacBook, discolouration and a "moo" sound. Last week Apple said it would recall nearly two million lithium-ion laptop batteries using Sony components after some of the batteries caught fire.

It isn't clear whether the shutdown problem is as serious as those issues, or whether it is a collection of similar, unrelated problems. Users have linked their shutdowns to particular applications, the heat sink and the power adaptor, among other things.