Five kinds of full-body scanners were tested at Narita Airport from July to September, and the ministry concluded that one of them was as effective as a pat-down check in detecting suspicious items.

The device emits millimeter waves, a kind of electromagnetic wave, to clearly depict passengers' body contours, it said.

To protect people's privacy, the ministry has set conditions for airline companies to introduce the device.

These include having officials of the same sex scan men and women in separate rooms and destroying the images immediately after inspection.

Passengers who do not clear regular airport metal detectors will have to choose a body scanner inspection or a pat-down as an additional check.