Facebook is considering incorporating most of its 1 billion-plus members' profile photos into its growing facial recognition database, expanding the scope of the social network's controversial technology.

The possible move, which Facebook revealed in an update to its data use policy, is intended to improve the performance of its "Tag Suggest" feature. The feature uses facial recognition technology to speed up the process of labelling or "tagging" friends and acquaintances who appear in photos posted on the network.

Facebook: Plans to introduce facial recognition to profile pictures.

The technology currently automatically identifies faces in newly uploaded photos by comparing them only to previous snapshots in which users were tagged. Facebook users can choose to remove tags identifying them in photos posted by others on the site.

The changes would come at a time when Facebook and other internet companies' privacy practices are under scrutiny, following the revelations of a US government electronic surveillance program.