The Thanksgiving holiday could turn fractious in airports all across the United States this week as public mutiny mounts over the recent introduction of new body scanners that leave little to the imagination and more thorough pat-down procedures at already congested checkpoints.

The furore has divided the country between those who believe security comes first and that probing, prodding and scanning is acceptable, and others who consider a line has been crossed into groping, exposure and touching of private parts that might amount to sexual molestation.

It was inflamed by one sentence uttered by a California man arriving for a flight in San Diego a week ago that has become a rallying cry for those now in rebellion. "If you touch my junk I'll have you arrested," he told a security officer. A stand-off ensued with the passenger, identified as John Tyner, a former professional cyclist, going back home rather than putting his "junk" at risk of contact.

Bloggers, members of Congress, civil rights advocates and even some pilots are joining to protest the new technology and procedures that have been phased in in response both to the attempted underpants bombing last Christmas as well as recent cargo-hold scares. A campaign is growing on the internet for passengers next Wednesday to refuse en masse to submit to the inspections.

"Where will it end?" asked John Mica, a Florida Congressman. "Shoe bomber, we had to take off our shoes; liquid, we have to take out our liquid; now we're being groped because of the diaper bomber. What's next? The proctologist, the gynaecologist?"

Assailed from all sides, the head of the Transport Security Administration (TSA), John Pistole, defended the changes this weekend. "We're trying to see everybody can be assured that everybody else on that flight can be properly screened," he said. The TSA website directed visitors to a USA Today poll showing the measures are supported by most Americans.

Thousands will get their first taste of the revamped security operations next week as Americans begin their annual pilgrimages to family and friends, often by air. More Americans take to the skies and the roads at Thanksgiving than at any other time of the year.

Among those up in arms are pilots who must submit to screening every time they show up for work. Two pilots last week filed suit against the government to be exempted from the scans. Pistole has conceded the TSA is taking their complaints into consideration.

"We've had a number of very good discussions with pilots and hope to be announcing something very soon in terms of a good way forward for the pilots," he said.

Regular passengers aren't likely to get the same kind of relief, however. So far the new all-body scanners, which undress the traveller much like a medical x-ray does, have been introduced in 60 airports. The more intrusive manual body-search guidelines are in force everywhere. Passengers are selected for a thorough pat-down either randomly or because something has shown up on the images collected by the body-scan machine. For travellers with particular medical issues, such as a prosthetic limb or insulin pump, a pat-down will come with every flight. Aside from the privacy issues raised by the scanners, some have also warned of the possible ill-effects of radiation.

Stories of humiliation abound. Erin Chase of Ohio, for example, has been quoted complaining that her vulva was touched. The agent "went to the bottom of my legs, came up my inner thighs, touched my genital areas on both sides", she said. "Security is obviously everybody's number one priority, but I don't think we need to be sexually violating our own citizens."

Ron Paul, the Texas libertarian, has introduced a bill on Capitol Hill to curb the new procedures. Called the American Traveller Dignity Act, it would end immunity from prosecution for TSA employees accused of molestation.

"If you can't grope another person, if you can't x-ray people and endanger them... if you can't take nude photos of individuals, why do we allow the government do it?" he asked.

The American Civil Liberties Union has also taken up the cause. "I would be very surprised if the average American would say this is okay after going through the kind of experience we're hearing about," said an ACLU policy analyst.