Human rights organisations from Europe, North America, Australia and Asia have sent an open letter to the International Civil Aviation Organisation (ICAO) railing against plans to create an international "identity register" that would force the inclusion of biometrics and controversial RFID tracking tags in all passports by 2015.
Among the 39 groups who put pen to paper are: Privacy International, the Foundation for Information Policy Research, the Electronic Frontier Foundation and the American Civil Liberties Union.
The ICAO will be meeting in Cairo next week and will be discussing the scheme. If the ICAO approves it, facial mapping and tracking tags would become mandatory, with fingerprinting also on the drawing board, depending on the preferences of individual governments.
Home Secretary David Blunkett has already proved his fondness for biometrics of all kinds when he announced late last year that there would be trials for biometric ID, with iris or fingerprint recognition potentially on the cards.
The US has also gone big on biometrics, photographing and fingerprinting visitors crossing its borders.
As well as voicing fears that the proposed database may "threaten [human] rights", the letter adds that the chosen standard of facial recognition may be unsound.
"The ICAO standards do not govern the use to which the facial recognition is put but even the most reliable uses of this technology - one-to-one verification using recent photographs - have been shown in US government tests to be highly unreliable, returning a false non-match [where technology doesn't recognise people with a valid photo] rate of five per cent and a false match rate of one per cent," it says, adding that there may be the potential for oppressive regimes to get their hands on methods of surveillance that were previously inaccessible.
"We hope that the choices of biometrics have been driven primarily by logistical and commercial concerns and were not intended to facilitate the conversion of travel systems into a global infrastructure of surveillance. But we are deeply concerned that this may become their unintended consequence," it concludes.