A veteran Apple watcher based in Minneapolis says the new flagship iPhone may be in short supply for months.

Supplies of the iPhone 5s, distinguished by a fingerprint reader and an improved camera, are so scarce that Apple Inc. may not catch up to demand until December, Gene Munster, an analyst at Minneapolis-based Piper Jaffray & Co., said in a report Thursday.

At Apple's online stores in the United States, United Kingdom, France, Germany, Canada, Australia, Hong Kong, Singapore and China, the iPhone 5s is showing an October expected shipping time, Munster wrote. In addition, the most popular 5s model, which has a case that is partly gold-colored, was sometimes listed as unavailable, he said.

As a result, the scarcity of the iPhone 5s model appears to be mirroring the shortages of the iPhone 5 a year ago. It took the company until December to catch up to demand then, Munster noted.

Munster earlier this week parsed Apple's publicly stated sales figures and disputed the company's claim that it sold 9 million iPhones last weekend, the first time that the 5s and the colorful iPhone 5c were available. He had predicted that 5 million to 6 million of the new iPhones would be sold over the first weekend.

Munster's explanation for the discrepancy was that about 3.5 million of the iPhones Apple counted as sold were in the inventory of resellers like Verizon Wireless and AT&T. That meant 5.5 million were purchased by consumers, in line with his expectations.

However, citing Apple's guidance and last weekend's data, Munster raised Piper's revenue estimate for Apple by 4 percent to $36.7 billion for the July-to-September period. He also raised its earnings per share estimate for Apple to $7.75 from $7.40 for the period.