Consumer interest in the 3G iPhone is nearly four times more than that of its 2G predecessor.
More than 130,000 people have pre-registered on O2's website since the phone was unveiled one week ago.
Only 35,000 people pre-registered their interest in the previous phone between its unveiling on 18 September and 9 November 2007, when it went on sale in the UK.
A spokeswoman for O2 said: ‘The interest is from a mixture of existing iPhone customers, existing O2 customers and new potential customers. People are signing up for email alerts about new products.’
She added: ‘There was no existing iPhone before the launch of the first version so it is hard to know how much bigger the extra interest is in the new handset.’
Many consumers were put off by the £269 initial price for the first iPhone, so Apple has allowed O2 to heavily subsidise the new handset for contract customers, giving it away free on some contracts when it goes on sale on 11 July.
Carphone Warehouse has similarly seen a big increase in people pre-registering for the 3G iPhone compared with the device’s predecessor.