Rob Merrifield, minister of state for transport, said 44 scanners ordered on Tuesday will be used on passengers selected for secondary screening at Canadian airports.

CBC News has confirmed that the machines, which can scan through clothing, be installed in Vancouver, Calgary, Edmonton, Winnipeg, Toronto, Ottawa, Montreal and Halifax.

The system, tested over the last year in British Columbia at the Kelowna Airport, allows a screening officer to see whether someone is carrying plastic explosives or other dangerous items.

The plan to use the technology has stirred controversy because the scanner produces a three-dimensional outline of a person's naked body.

Privacy concerns addressed

Chantal Bernier, the assistant privacy commissioner, said in October the national air-security agency had successfully answered her office's questions about the project. Under the plan approved by the privacy chief, the officer would view the image in a separate room and never see the actual traveller.

Only people singled out for extra screening would be scanned, and they would have the option of getting a physical search instead.

Merrifield and Transport Minister John Baird said after an individual has successfully passed through the scanning, the information and images will not be stored, transmitted or printed in keeping with Canada's privacy laws.

The scanners cost $250,000 each, including parts and training. The first 12 scanners ordered will arrive next week, said Baird, with the remaining 32 coming over the next six to 10 weeks.

Baird said it takes about five days to train airport personnel to use the machines.

Transport Canada will also set up an airport watch system to look for suspicious passengers and tab them for enhanced screening, Baird said. He said the new system will not affect passengers under 18 years of age.

Screening process concerns privacy groups

Bernier told CBC News the behavioural screening process introduced Tuesday was not part of its October review and said the Office of the Privacy Commissioner will be discussing the issue with the Canadian Air Transport Security Authority.

"We intend to keep a close watch on this file," she said.

Canadian Civil Liberties Association general counsel Natalie Des Rosiers said she had concerns about the behavioural screening plan, which she says could be used to single out certain groups for racial profiling.

She also had concerns that while the government has portrayed the scanners as optional, security officials may change their minds and make the scans mandatory after their implementation.

Canada examining U.S. rules carefully: Harper

Security personnel using the scanners will see images like these when passengers pass through the scanners. (CBC)

Transport Canada said Monday that the enhanced security measures on flights to the U.S. will remain in place until further notice. People flying into the U.S. are not allowed to bring carry-on bags into the cabin of the aircraft, with some exceptions, such as coats, medication and items for infant care.

Travellers to the U.S. from Yemen, Nigeria, Saudi Arabia and 11 other countries face full body pat-downs before boarding.

Meanwhile, the U.S. government could be looking at more airport security measures.

"We're going to take a look at these measures very carefully and we may arrive at different conclusions," Prime Minister Stephen Harper said in an exclusive interview Tuesday with the CBC's Peter Mansbridge.

"It's my hope as we look at these things which, you know, invariably will cause some changes in mass procedure, that we make sure that we respond in ways that are intelligent, in ways that identify threats before they happen."

The focus on security measures stems from the failed attempt by a Nigerian man to set off a bomb on a flight from Amsterdam to Detroit on Christmas Day.

Umar Farouk Abdulmutallab, 23, is accused of trying to ignite the bomb on the Northwest Airlines flight. Officials said he has told U.S. investigators he received training and instructions from al-Qaeda operatives in Yemen.