Hong Kong tourists heading to South Korea on Wednesday said they were not fazed about the short-lived martial law in the country as the government called on residents to remain cautious.

South Korean President Yoon Suk-yeol ended martial law hours after the declaration last night.

In Hong Kong, flights for South Korea were operating as usual.

A woman surnamed Wong was heading to South Korea alone.

She admitted she was a bit worried when martial law was declared, but noted that it was short-lived.

She believed the situation in the country should be fine.

"I plan to check the news before I head out," she said.

"I will also try to avoid places with crowds, as my friends told me that if I see people gathering, I should not get close."

A woman surnamed Cheung told RTHK that she's not too concerned about the situation, adding that whatever happens, happens.

Another Hongkonger, surnamed Law, believed she will be safe as long as she stays away from protests.

She said if anything happens, she will stay in the hotel.

Some Koreans in the SAR said they were shocked about the declaration of martial law.

Mr Park, who's in the region with a friend for a taekwondo competition, said he and his pal were sceptical about the news when it broke.

"We [thought] that it's not real situation. [We thought] it's fake. We talked to each other that it's fake news. But it's a real situation. So we are very surprised. About 40 years ago, you know that Korea is under the military government, but Korea is very developed economically and politically," he said.

"And democracy, we Korean people made democracy. So we believe that this kind of situation cannot be real and cannot stay [for long]. So we are very happy to see that the situation is over."

The Travel Industry Council said around 400 people from 26 tours groups are in South Korea.

Their trips have not been affected and there are no plans for them to return to Hong Kong earlier than scheduled.

The council has not received any requests for assistance.

Still, the SAR government urged Hong Kong residents who are in the country or plan to go to South Korea to remain cautious.

"[They should] monitor the situation, exercise caution, attend to personal safety, avoid large gatherings of people and pay attention to local announcements on the latest situation."

The Security Bureau said social order in South Korea is normal for now, and it would closely monitor the situation.

So far, no one has asked for assistance from the Immigration Department.