A blue banner (top R) outside a grocery shop in Seoul reads 'Japan - a country that does not regret its past. We do not sell Japanese products here [Photo, AFP]

Beer-loving South Koreans angered by a trade row with Tokyo are boycotting Japanese brews in a surge of patriotism that has even seen popular beauty bloggers targeted.

Japan this month unveiled tough restrictions on exports crucial to tech titans like Samsung, fuelling fears about the impact on the global tech sector, while South Korea's central bank warned it could have "no small impact" on the economy.

Officials from both countries have held hours of terse talks to settle the worsening crisis but there has so far been no sign of a detente.

But beer drinkers in the South are making their fury known, shunning four big Japanese brands in favour of other brews, according to E-Mart, the country's largest hypermarket chain.

Sales of Asahi, Kirin, Sapporo and Suntory beer fell nearly 25 percent in the first two weeks of July compared with the second half of June, it said.

"This is a sudden drop we haven't seen for a long time," an E-Mart official told AFP, adding that sales of Korean beer brands were up around seven percent in the same period.

The trade spat is the latest escalation in a bitter decades-long feud over Japan's use of forced labour during World War II.

It has sparked ire in South Korea, where almost seven in 10 people still report negative feelings towards the country's former colonial ruler.

Meanwhile around 3,700 members of a South Korean grocery store owner association have stopped orders of some or all Japanese products.

"Japan -- a country that does not regret its past. We do not sell Japanese products here," reads a sign in front of one supermarket in Seoul.

The shop's owner, Kim Jeung-pil, told AFP he had removed beer and cigarettes produced in Japan from sale this week -- the first time he has taken direct action in this way.

"Asahi beer has always been very popular among my customers," he said. "But I'm willing to make this sacrifice for my country."

- Made in Korea -

Tokyo says its trade restrictions -- targeting key chemicals used in making gadgets -- were made necessary by a "loss of trust" in relations with Seoul, while also accusing South Korea of improperly handling exports of sensitive materials from Japan.

But Seoul says Tokyo was retaliating for a series of rulings from South Korean courts ordering Japanese firms that used forced labour decades ago to compensate the victims.

Among the boycott calls is an image shared on Instagram that says "I won't go to Japan, I will not buy Japanese products", featuring the word "NO" with the Japanese flag's red disc as the "O".

One of the biggest online forums for South Korean visitors to Japan, where more than a million users share travel tips, also announced an indefinite closure in support of the movement.

South Korean stationery chain Kyobo Hottracks has started indicating which pens are domestically produced by labelling them with markers featuring the national flag or flower.

It told AFP sales of Korean pens increased 23 percent in the week after they first put them out, while sales of those by Japanese brand Jetstream dropped by 10 percent.

Even beauty bloggers have come under scrutiny. Risabae, whose video channel has more than two million subscribers, had to apologise after public criticism for demonstrating a Japanese make-up product earlier this month.

- National identity -

South Korea and Japan are both democracies and US allies, faced with an increasingly assertive China and the long-running threat of nuclear-armed North Korea.

South Korea's left-leaning President Moon Jae-in is pushing for engagement with the North and has stressed that the independence struggle against Japan is at the heart of national identity in both Koreas.

Meanwhile supporters of the Japanese administration are more right-wing and revisionist, said Linda Hasunuma, an assistant professor of politics at the University of Bridgeport in the US.

"We have two governments that are willing to escalate tensions as they try to respond to their bases," she told AFP.

In Japan, a poll of around a thousand people by the Asahi Shimbun newspaper found that 56 percent supported the government's tightening of export controls to South Korea on chemicals used for chips.

Not all South Koreans support the boycott of Japanese goods, however.

Jeong Deok-rye, a 52-year-old restaurant owner in Seoul, said customer complaints had forced her to remove Asahi beer from the menu.

"One customer said just by looking at Asahi beer, it makes them angry," she told AFP, adding that she hopes South Korea and Japan end their animosity so that "both of the countries prosper".