The Japanese version of Apple’s iTunes Music Store got off to a rip-roaring start with sales hitting 1m tracks in its first four days online.

In contrast, the Sony-affiliated Mora service recently said downloads were running at about 450,000 songs per month.

The Apple service was opened last Thursday by Steve Jobs, Apple's CEO, at an event in Tokyo and received considerable coverage on local television and newspapers. Jobs said in a TV interview that he is confident that iTunes will become the leading music download website in Japan.

Part of the strong start is perhaps due to pent-up demand. Apple's iPod is the top-selling digital music player in Japan and users have had to wait more than two years since iTunes Music Store opened in the US for the Japanese store to begin business.

The launch was held up by negotiations with local record companies, Jobs said on Thursday.

Apple has lower prices to show for the negotiations. About 90 percent of music offered in the iTunes Music Store costs ¥150 (75p), compared to between ¥210 (£1.05) and ¥315 (£1.58) on competing services like Mora.

However, more negotiations may be needed. Apple has the support of about 15 local record labels at present but many of Japan's top music companies aren't yet on board and that means many of the most popular Japanese acts are missing from the service.