Using facial recognition to figure out how long people will wait in a queue is like using a sledgehammer to crack a nut.

That's according to the Privacy Commissioner who has serious concerns about the scanning tool being used at Wellington Airport.

The tool is used to count passengers passing through security and how long they wait in a line.

The Civil Aviation Authority said it's committed to providing transparency with the public and appreciates there are concerns, but there are strict measures in place to protect people's privacy as they move through the terminal.

Midday Report's Michael Cropp asked the Commissioner John Edwards about his feedback to Aviation Security.