Apple Computer last night said that quarterly profits had trebled on the back of higher sales of its iPod digital music player, the must-have gadget of the moment.

The company posted earnings for its second quarter of $46m (£25m), up from $14m in the same period a year earlier. Revenues increased to $1.9bn from $1.5bn. The better than expected results pushed Apple's shares 6% higher in after-hours trading.

Apple sold 807,000 iPods, an increase of more than 900%, reflecting how rapidly the handheld devices have become popular. Revenues from the iPod were $264m, up from $31m. Apple has sold about 2.8m since the gadget was first introduced in 2001.

Sales were given added momentum after Apple launched its pay-per-download iTunes online music store in the US in April last year. The company was unable to keep up with demand at Christmas, leading to shortages.

The iBook, Apple's distinctive white laptop, also performed well, reporting revenues of $223m, up 48%. Sales of the Power Mac computers rose 19% to $349m.

The company is introducing a smaller lighter version of the iPod, called the iPod Mini.