Online retail colossus Amazon is seeking a US patent on using selfies -- instead of passwords -- for shopping when using smartphones.

Seattle-based Amazon reasoned that combining sensor and camera capabilities in smartphones with face and gesture recognizing software results in higher security than passwords or identification numbers.

"Such approaches provide for user authentication without the user having to physically interact with a computing device, which can enable a user to access information by looking at a camera, performing a simple gesture such as a smile, or performing another such action," Amazon said in a patent application filed late last year.

"Such an authentication can be user friendly, particularly with respect to conventional approaches such as typing and remembering long passwords, and can provide enhanced security because it can be difficult for another person to replicate a user's face in three dimensions."

Smartphone cameras would capture video snippets to avoid being duped by a fraudster using someone's picture to impersonate them in an online transaction, according to the patent application.

"The device can prompt the user to perform certain actions, motions, or gestures, such as to smile, blink, or tilt his or her head." the patent application said.

Chinese internet giant Alibaba and payments payments firm Mastercard are reported to be working on incorporating facial recognition in transaction confirmations.