The Department of Homeland Security will trial a new biometric departure procedure next month at two US airports.

If successful, it will replace the departure portion of the current I-94 Green Card, which is due to be phased out after ESTA becomes mandatory.

Customs officials at Detroit and Atlanta airports will use mobile devices to record biometric data from departing passengers, which will be matched to the finger scans and digital photo taken on arrival.

The new system follows an unsuccessful scheme for passengers to provide their own data on departure, which was tested at 12 US airports two years ago.

Homeland security director of legislative affairs Matthew Coughlin said the new scheme, if successful, could roll out across the US in a year’s time.