AS IPHONE fans await the release of a new model, they are delaying purchases and may cause Apple, the world's largest company by market value, to post its slowest sales and profit growth in more than two years later today.

With a redesigned model probably arriving by October, analysts estimate that sales of iPhones - Apple's biggest source of revenue - slid in the financial third quarter from prior periods. While analysts predict that the next iPhone will be the best-selling smartphone yet from the California-based Apple, the purchasing delays will probably weigh down results until the device hits shops.

"People are waiting," said Andy Hargreaves, an analyst at Pacific Crest Securities. Apple would sell about 25,4-million iPhones, he estimated, compared with 35,1-million in the previous quarter. "It's going to be bad now, but great later."

A similar slowdown occurred ahead of last year's iPhone 4S release in October, causing Apple's shares to slide when the company reported profit that fell short of analysts' estimates for the first time since 2003.

Apple has not said when it will unveil a new iPhone, and has given no details about plans for the product. Yet the dip in unit sales underscores how speculation about Apple's plans, including a slew of websites dedicated to publishing rumours about new devices, can lead potential buyers to sit on their wallets while waiting for a new product.

"Customers are increasingly tech savvy and they want to have the latest and greatest," said Anthony Scarsella, the chief gadget officer at, a website that buys and sells used iPhones. He said people wind down trading in their iPhones about four to six months ahead of an iPhone release.

Apple will probably report profit growth of 35% to ¤9,86bn today, according to the average of analysts' estimates. Sales are projected to rise 31% to ¤37,3bn. While that kind of growth would outpace gains by most of Apple's technology peers, it would be the company's slowest since 2009.

Another potential barrier to near-term sales besides waiting to upgrade, was a weak global economy that crimped consumer spending, as well as changes by carriers that extend how long a customer must wait to get a subsidy for a new device, Mr Hargreaves said.

Apple also is facing competition from rivals including Samsung Electronics, which according to NPD Group is the world's biggest seller of smartphones. Samsung released the Galaxy S3 phone in May.

Still, Wall Street analysts have a history of underestimating Apple's results. The company's earnings have exceeded average estimates every quarter except one since at least 2003, according to data. Investors are shrugging off concerns about Apple's quarterly results and are instead looking ahead to the next iPhone, according to Gene Munster, an analyst at Piper Jaffray. So far this year, Apple's shares have risen 49%. He said more than 80-million iPhones would be sold when the new model is released.

Mr Munster said iPhone sales may be better than many analysts are projecting in the financial third quarter, in part because of demand in China, where the device went on sale in January and is now Apple's second-largest market behind the US.