NEW YORK (Reuters) - U.S. consumers who want the new iPhone but cannot or do not want to sign up for a two-year contract with AT&T Inc will eventually be able to buy it for an extra US$400 (S$545).

Apple Inc has said the new iPhone will go on sale July 11 at US$199 (S$271) for the model with 8 gigabytes of storage and US$299 (S$408) for the 16-gigabyte version. These prices apply to customers signing up for a two-year AT&T contract.

Those who don't want to be locked into such a contract, or do not have adequate credit, can buy the iPhone for US$599 (S$817) or US$699 (S$953) as long as they sign up for some kind of AT&T wireless subscription, AT&T said on Tuesday.

An AT&T spokesman could not yet say when that option would become available.

(Reporting by Ritsuko Ando; editing by John Wallace)