A staff member at the Netherlands Embassy said it had not received any complaints from its citizens resident in Korea.

"We've not been updated about such a policy and also why it was introduced," a ministry official said, asking not to be named. "But even if we knew about the background regarding the policy, we would not be able to comment on it because we don't want to appear to be intervening in another country's affairs."

Meanwhile, the Chinese Embassy in Korea has not sufficiently notified anybody about the new visa rules, as the Ministry of Foreign Affairs and the Netherlands Embassy in Korea were unaware of it until contacted by The Korea Times.

"Targeting foreigners in Korea over THAAD would mean China picking a fight against the rest of the world," said Shin In-kyun, president of the Korea Defense Network. "It would be too risky to relate THAAD with the enhanced visa rules on foreigners."

"I'm not sure, but of course it's possible," he said.

"Instead, citizens of the Republic of Korea (ROK) and other foreigners in the ROK have to apply for a Chinese visa through travel agencies designated by the Consular Section of the Chinese Embassy, it said on its website.

Additionally, on Aug. 23, the Chinese Embassy in Seoul decided to no longer accept individual applications for visas for various purposes, including travel, business, study and work from Sept. 1.

Although Beijing has denied it, China is suspected of enforcing new visa rules on Koreans since 2016 when Seoul and the U.S. jointly agreed on the THAAD deployment.

Two international students from Switzerland and Sweden planned to travel to China but were refused a visa because their cards had not been issued yet, according to Seoul Global Center.

"When I was at the visa center, there were many people of different nationalities in the line who could not get it," he said.

Varkevisser claimed he was not the only person to be inconvenienced by the new rule.

He said the Chinese Visa Application Service Center at Seoul Square building in Jung-gu, referred to a "system upgrade" as the reason for refusing to issue him a visa, but refused to give any details. "The real reason was not given," he said.

"There are many people who come and spend one week in China, another in Korea and some days in Japan. And the new policy causes more inconvenience for tourists who come to China, Japan and Korea on holiday," he added.

"I already had booked the flights for $800 for this week and now I can't visit China with my business partner.

"It is no longer possible for foreigners in Korea without an alien registration card to apply for a Chinese tourism or business visit single entry, double entry or multi-entry visa," Varkevisser told The Korea Times last week.

This suggests the best way for the people like Varkevisser to get a Chinese visa is to apply for it in their home country before leaving for Korea. Varkevisser claimed that he was not informed of the new visa policy in advance until his request was denied.

According to the KIS, only those who are staying in Korea for more than 90 days and hold appropriate visas can apply for the card.

For Varkevisser and other foreigners who are not long-term residents here, the rule is "absurd" because they are not entitled to the alien registration card, which is only for long-term residents.

However, Varkevisser was not aware of the rule change like most other foreign visitors who want to use Korea as a stopover for a visit to China.

The new rule requires any foreigners applying for a Chinese visa in Seoul, regardless of the purpose of their visit or the number of allowable entries, to have an alien registration card issued by the Korean Immigration Service (KIS).

The Chinese Embassy in Seoul explained the country has changed its visa rule for foreigners who want to visit China via South Korea.