The company posted a notice to its site which said that the Apple handset would face shortages " for the foreseeable future."
O2 said that it was receiving weekly shipments of the handsets from Apple, and would continue to do so. Still, however, the iPhone 3G is in such high demand that the device would only be sold in O2's retail outlets.
"We will continue to sell iPhone 3G's on a first come, first served basis to be fair to all customers," the company said.
"We are confident that all customers who want an iPhone 3G will get one by the end of the summer.'
The retail only policy will also apply to the iPhone upgrade program, which lets users trade in the first-generation iPhone for the new handset in exchange for an extended commitment on their contract.
iPhone buyers in the UK can also obtain the handset from Carphone Warehouse and Apple retail stores.
O2's struggles are only a small part of a worldwide iPhone 3G shortage. US carrier AT&T has warned of similar shortages and is currently estimating that customers are waiting two weeks for an order to be processed.
Analysts have predicted that the shortage could last well into August.
O2 still reeling from iPhone rush
By Shaun Nichols on Jul 28, 2008 1:56PM