European Union states should refrain from using full-body scanners at airports until the bloc can agree on rules to protect the privacy and health of passengers, the EU's transport chief-designate said Thursday.

"It's very bad that some countries already use them without common agreed standards," Estonian nominee Siim Kallas said during his European Parliament confirmation hearing.

Pressure to increase airport security has risen since the thwarted Christmas Day bombing of a flight from Amsterdam to Detroit. In response, Britain, the Netherlands, France and Italy have announced plans to use full-body scanners.

Amsterdam airport operator Schiphol Group has 15 of the devices in use and wants to buy 60 more.

There is no EU-wide obligation to install them and the European Parliament has strongly opposed previous plans to promote the devices, which produce an image of the body underneath clothes.

Kallas, 61, echoed comments by justice commissioner-designate Viviane Reding earlier this week that out of concern for privacy protection EU states should not rush to install the scanners.

France said last week it would use scanners to search passengers travelling to the United States from some of its airports, while Britain plans to install them at London's Heathrow Airport and Italy wants to equip Rome and Milan.

The executive European Commission is preparing a report on the impact on health and privacy of full-body scanners, which Kallas said should be ready in a few months.

Reding and Kallas along with other nominees for 26 EU commissioners face a confirmation vote on January 26.

The United States is pushing for greater use of the devices, which use radio waves to project a three-dimensional image, as part of its effort to beef up international air travel security.

Washington has put in place extra screening for U.S.-bound travellers from several countries including Nigeria. A Nigerian man has been charged with the failed attack on December 25.