OTTAWA - The government will install dozens of scanners that can peer through the clothes of travellers in airports across Canada.
It will also set up an airport watch system to look for suspicious passengers and tab them for further screening.
"We've got to stay ahead of the terrorist elements," Transport Minister John Baird said Tuesday in announcing plans to buy 44 of the $250,000 machines.
The announcement was part of an international response to a Christmas Day attempt by a Nigerian man to blow up a jetliner over Michigan by igniting explosives sewn into his underwear.
"We must remain vigilant," Baird said.
The United States has already demanded tighter screening of passengers from 14 countries, including Nigeria. Canada has banned carry-on bags for U.S.-bound air passengers.
Britain also wants to deploy the scanners at its airports, but the government has run into opposition over privacy concerns. Canada's privacy commissioner doesn't share those worries.
Baird and Rob Merrifield, junior transport minister, said the scanners will only be used for passengers singled out for secondary screening. And people who don't want to go through the machines can opt to be frisked instead.
The scanners will first be installed in Vancouver, Calgary, Edmonton, Winnipeg, Toronto, Montreal, Ottawa and Halifax and will all be in place in by spring.
The system, tested in British Columbia at the Kelowna airport, enables a screening officer to see whether someone is carrying explosives or other dangerous items.
Last week officials said there were no plans to speed up consideration of the long-discussed scanners in light of the near-disaster in Michigan.
But the government, under pressure to respond to the dramatic U.S. incident, has decided to make the multimillion-dollar purchase.
"We are ensuring that Canadian officials will have the tools to do the job," Merrifield said.
The proposal has stirred controversy because the scanner produces a three-dimensional outline of a person's naked body - prompting some to denounce the process as a virtual strip search.
The system received the blessing of the federal privacy czar in October.
Under the plan approved by the privacy chief, the officer would view the image in a separate room and never see the actual traveller.
Merrifield said the images will automatically be erased after the scan. No copies will be made or kept.
Chantal Bernier, the assistant federal privacy commissioner, told a conference late last year that the holographic image generated by the scanner makes it difficult to identify the traveller's face.
"You would not know who it is, even if you knew the person was in line," she said at the annual meeting of the Canadian Association for Security and Intelligence Studies.
In addition, the image would be deleted the moment the person leaves the screening portal.
"In our view, these privacy safeguards meet the test for the proper reconciliation of public safety and privacy," Bernier said.
The scanners are already in use at airports in cities including Amsterdam, Moscow and Phoenix. They are also found in the high-security "green zone" of Baghdad and at some U.S. courthouses and prisons.
Bernier added that the Canadian Air Transport Security Authority had done thorough threat assessments that revealed a need to search passengers for weapons that might elude a conventional metal detector.
The privacy commissioner's office recommends a public education campaign to explain the machines, and says minors would be scanned only with the consent of guardians accompanying them.
The air security authority says the low-level radio frequency wave emitted by the body scanner meets Canadian health-and-safety standards.