US Bank is to offer certain customers in two cities in the States the opportunity to make NFC-based mobile payments by fixing special cases to their iPhone 4 or iPhone 4S.

The bank said the beta service will be available to US Bank ‘s FlexPerks Visa customers in the cities of Salt Lake City, Utah, and Portland, Oregon. The service will be launched “more broadly in 2013”.

Users attach the case, which is supplied by DeviceFidelity, to the two iPhone models and can then make payments at outlets which have incorporated Visa payWave technology into their point-of-sale terminals. A case for the iPhone 5 is not yet available.

Salt Lake City is also one of two cities where Isis, the venture backed by three US operators, is trialling its mobile payment services. It also plans to offer the DeviceFidelity case to users.