Apple has officially delayed the release of Mac OS X 10.5 'Leopard' until October this year, and says the release of the iPhone is to blame for the delay.

A statement on Apple's website explains: "iPhone has already passed several of its required certification tests and is on schedule to ship in the US in late June as planned. We can’t wait until customers get their hands (and fingers) on it and experience what a revolutionary and magical product it is. However, iPhone contains the most sophisticated software ever shipped on a mobile device, and finishing it on time has not come without a price — we had to borrow some key software engineering and QA resources from our Mac OS X team, and as a result we will not be able to release Leopard at our Worldwide Developers Conference (WWDC) in early June as planned."

The company continues to explain that while the new OS will be feature-complete by June, the company can't promise to deliver the high-quality of OS its customers have come to expect.

There's good news for developers attending WWDC – Apple will give them a beta copy of Mac OS X 10.5 so they can continue product testing, and will ship Leopard "in October", the company said.

"We think it will be worth the wait. Life often presents trade-offs, and in this case we’re sure we’ve made the right ones."

Analysts spoken to by MacCentral weren't particularly moved by this news. “A delay in an operating system is not much to worry about,” said Tim Bajarin, president of Creative Strategies. “If they were a year late, I’d be concerned, but not a few months.”