Apple's claim that it sold one million 3G iPhones in the first three days of sales is being disputed.

According to PC World New Zealand it looks like Apple scored a local sell-out, but Piper Jaffray analyst Gene Munster has calculated the actual number of iPhone sales globally to be less than half a million after surveying US stores and calculating how many iPhones had been activated.

It seems the issue comes down to the definition of "sold".

Apple appears to count all iPhones sold into its channel as sold, even though some have yet to be bought by end users. Apple sells into its own stores, but also to wireless operators around the world, including AT&T in the US and Vodafone in New Zealand.

Piper Jaffray estimates sales to end users at 425,000.