Temu's online advertisement shows that the Nintendo Switch gaming console sells at a mere 999 won ($0.72). Screen capture from YouTube

AliExpress and Temu are catching flak from customers for a series of misleading and deceptive advertisement campaigns, which prompts calls for the nation's antitrust agency to take punitive measures against the two Chinese e-commerce firms, according to customers and industry officials Wednesday.

The two overseas shopping platforms have made rapid strides in the Korean market this year. But consumers have complained over "too frequent" appearances of their advertisements on social media, such as on YouTube and Instagram.

They have particularly expressed complaints over the two firms' flagrant clickbait ads. For instance, Temu is drawing customers' backlash for repeatedly exposing its tricky ad for the Nintendo Switch video game console selling for merely 999 won ($0.72). The portable gaming device sells at 360,000 won on its official website.

"The ad says you can purchase the device at the special sales price, but you have to attract dozens of your friends to sign up for the Temu app to win the benefit," a Temu user said. "The marketing gimmick reminded me of a pyramid scheme. I never found anyone who actually succeeded in buying the product at the price, even if the company may have done so for only a small number of people."

AliExpress also came under criticism for running a deceptive membership service. The company promoted a "free trial" period for 30 days, but the company then charged $19.90 to those who had applied for the service without giving further notice at the end of the trial period.

Calls have been raised for the Fair Trade Commission (FTC) to promptly slap sanctions on AliExpress and Temu to dissuade them from employing deceptive marketing campaigns to which customers fall financial victim.

An official from a retail company here argued that the government should sternly punish overseas players for such confusing and delusive sales practices on an equal footing with domestic players.

"Coupang was recently slapped with enormous fines of around 140 billion won, but Chinese players have yet to be strictly punished, even if they are continuously mired in a series of controversies, including the latest promotional gimmick and weak monitoring of their products," the official said.

Some have said this is reverse discrimination against home-grown firms, so the authority is urged to build more fair competition ground by imposing strong sanctions on Chinese players as well, according to the official.

"The Chinese companies were caught selling products containing carcinogenic substances, but the FTC merely signed a voluntary safety agreement without taking any immediate punitive measures," he said.

Responding to such complaints from domestic e-commerce firms, FTC Chairman Han Ki-jeong recently said the two Chinese firms are under investigation by the watchdog for their inappropriate sales activities.

"Our investigations into AliExpress and Temu's violations of local e-commerce laws will be finalized sometime in late June and July, respectively," Han told reporters last week.