A South Korean entertainment company, criticised for its handling of a row over a teenage Taiwanese K-pop star forced to apologise for waving the island's flag, has had its website brought down by hackers, a spokesman said Tuesday.

JYP Entertainment, which represents the singer Chou Tzu-yu, said the company's homepage had been down since Saturday as the result of an apparent cyberattack.

"We're working to fix the problem but we don't know how long it will take to restore it," he said.

The company had been accused of coercing Chou into recording an online video apology after footage of her waving a Taiwanese flag triggered an angry reaction in China -- a key market for JYP.

Taiwan has ruled itself since a split with the Chinese mainland in 1949 after a civil war, but has never formally declared independence.

Beijing sees it as part of its territory awaiting reunification, by force if necessary, and Chou's flag-waving was see by some as a pro-independence gesture.

In her video, which was issued by JYP, a shaken-looking Chou bowed, apologised and stressed that there was "only one China".

The move sparked a backlash in both Taiwan and South Korea, with complaints that Chou had been unfairly targeted and criticism of JYP for kowtowing to China and exerting undue pressure on the 16-year-old.

JYP Entertainment denied it had "forced" her to issue an apology, but acknowledged it was party to her decision to so.

"Her parents visited Seoul and we had a three-way meeting with Chou and her parents," Kim said.

The row became a major topic of discussion in the final days of Taiwan's historic election, which saw the island elect its first female president on Saturday.