That selfie stick in your hand. A harmless memory-maker? Or a potentially chaos-inducing electromagnetic radiation emitter?

In South Korea, it seems, it could be both and anyone selling an unregistered version could face a $27,000 fine or up to three years in prison, the Science Ministry announced last week.

Regulating the sale of these small, articulated monopods designed for cell phone-wielding photographers won't be easy, given their numbers.

South Koreans have embraced the technology with a passion, turning scenic spots into undulating fields of waving selfie sticks and grinning, upturned faces.

The focus of the ministerial crackdown are those models that come with bluetooth technology, allowing the user to release the smartphone shutter remotely, rather than using a timer.

The problem, the ministry says, is that such units are designated as communications equipment given their use of radio waves to provide a wireless link between separate devices.

As such they have to be tested and certified to ensure they don't pose a disruption to other devices using the same radio frequency.

Ministry officials admit the crackdown is basically motivated by a technicality, given that the weak, short-range signals emitted by bluetooth devices are hardly likely to bring down a plane or interfere with police frequencies.

- 'Obligated to crack down' -

"It's not going to affect anything in any meaningful way, but it is nonetheless a telecommunication device subject to regulation, and that means we are obligated to crack down on uncertified ones," an official at the ministry's Central Radio Management Office told AFP.

Despite the harsh penalty on offer, the "crackdown" appears to have been relatively low-key, with no mass police raids on unsuspecting selfie stick vendors.

"The announcement last Friday was really just to let people know that they need to be careful about what they sell," said the official, who declined to be identified.

"We've had a lot of calls from vendors who think they might have been unknowingly selling uncertified products," he added.

South Korea is, in many ways, a highly regulated society, and people are generally used to a pervasive requirement for registration and certification.

Patrons of the country's many Starbucks outlets, however, protested loudly recently when it emerged that the personal data they must provide to link to the in-store wi-fi was not required of foreigners.

- Vendors unfazed -

Selfie stick vendors in Seoul appeared to be taking the ministry's order in their stride.

"I was told about the new regulation, but the ones I sell are all certified, so I haven't had any problems with the police or anything," said the owner of a small kiosk selling smartphone cases and selfie sticks near a subway station in Seoul's Myeongdong tourist district.

"But I know some of the bigger sellers had to get rid of some of their stock which hadn't been registered," said the owner who identified himself by his surname, Lee.

Vendors in a busy area of Myeongdong say they can shift scores of selfie sticks on a good day, but Lee said his normal turnover was rarely more than a dozen.

"They're not that profitable really. There're so many around now that you have to sell them cheap," he said.

A basic model sells for as little as $5.0 and the bluetooth-enabled versions go for $25 and up.

"Selfie" was chosen as the Oxford Dictionaries' word of the year in 2013, and the term is believed to have been coined on an Australian online forum in 2002.

South Koreans, however, claim a much earlier coinage, with the equivalent Korean term "sel-ca" -- a combination of self and camera -- having been in wide use since the 1990s.

It was heavily popularised with the rise of the K-pop scene whose stars were taking and sharing snaps of themselves long before Ellen DeGeneres engineered the ultimate celebrity-studded selfie at the 2014 Oscars.