Mobile financial services continue to gain momentum as American Express announced that it has added credit cards as a payment mechanism to the Isis mobile wallet venture in the US, while Samsung announced that it will be working with Visa to demonstrate NFC mobile payments at the London Olympics.

Last year the American Express network joined the Isis Mobile Commerce Platform; a joint venture between AT&T Mobility, T-Mobile USA and Verizon Wireless. The firm has now announced an agreement to make its US Consumer, OPEN Small Business and Serve Cards available on the mobile wallet platform.

“Now our Cardmembers and merchants can benefit from the ease and convenience of a tap-and-go experience on a mobile phone and still enjoy the benefits, services and support of American Express,” said Josh Silverman, president of the US consumer services division at American Express.

Meanwhile Samsung and Visa have also struck an agreement in their respective roles as worldwide Olympic partner for wireless communications equipment, and worldwide Olympic partner and exclusive payment services sponsor to provide Olympic athletes with a limited edition device that offers a more convenient way to buy goods at the event.

Samsung’s new device, the Galaxy SIII will be enabled with Visa’s mobile payment application, Visa payWave, and available for athletes and triallists sponsored by Samsung and Visa. Athletes will be conducting live demonstrations of the devices to the public at the event.

The firms said that by the time Olympic Games begin, there will be more than 140,000 contactless terminals around the UK for taxis, retail outlets and at the Olympic Park.