New See-Through Screening Device at Airport Shows Genitals

"It does see through clothing, but it's not a photographic image, it's a low-energy X-ray that reflects off the skin," said Cheryl Johnson, general manager of the Office of Transport Security.

"It will show the private parts of people, but what we've decided is that we're not going to blur those out, because it severely limits the detection capabilities. It is possible to see genitals and breasts while they're going through the machine, though."

However, Ms Johnson said there were a number of measures in place to tackle concerns about privacy.

"The faces are automatically blurred and ... it's only a chalk-style outline, it's not as invasive as some of the other equipment that we've got," she said.

"The security officer that's looking at it is located away from the screening lane, so there's no comparison of the person walking through and the image. The images are not saved, you literally walk through, the screener hits a button to say clear and the image goes."

Adelaide University civil liberties expert Allan Perry said the technology could breach people's privacy if used as a general measure for all passengers rather than those identified as a security risk.

"If this is done on a widespread basis without selectivity it certainly goes beyond an appropriate balance of personal privacy and security," he said. "Simply because something is being done for the purpose of security does not justify intrusive and invasive searches of people. If you said that everyone who wanted to board an aircraft would be physically strip-searched people would object. This is tantamount to the same thing."