ExpressPay uses RFID technology in the form of a chip-based keyring attachment or embedded in a traditional smart card to transmit payment instructions to merchant terminals. The user holds the key ring or card next to a reader to complete a purchase.

Ritz Camera will install ExpressPay across its 1300+ locations, beginning with stores in New York and Phoenix. Sheetz has already rolled out the ExpressPay system across its 305 convenience stores nationwide. In addition, the system will be switched on for payments at Sheetz petrol pumps by the summer.

American Express has been testing ExpressPay at merchant locations in the Phoenix area since 2002 and in New York since 2003.

Visa launched its own system in the US last month, although at the time no card issuers were offering the contactless payments cards and Visa declined to say whether any retailers have agreed to use the technology.

MasterCard's contactless PayPass system has been tested at McDonald's restaurants, among other locations, and is also being incorporated into the card loyalty programmes run by MBNA on behalf of the Seattle Seahawks and Baltimore Ravens.

Earlier this month both MasterCard and Visa agreed to share a common communications protocol for radio frequency-based contactless payments at the point of sale, based on the MasterCard PayPass spec.