China has shut down the Chinese website and app of Marriott International for a week, after the firm listed Tibet, Hong Kong, Macau and Taiwan as separate countries in its emails and app.
The hotel group has apologised for the error and said it did not support separatist movements in China.
Tibet, Taiwan, Hong Kong and Macau were listed as individual nations in an online survey sent to customers.
Beijing considers self-ruling Taiwan to be a breakaway province while Tibet is governed as an autonomous region. Hong Kong and Macau are both special administrative regions of China.
Chinese authorities say Marriott's wording violated cybersecurity and advertising laws. China's tourism ministry said it "attaches great importance to this incident" and immediately ordered an investigation.
It said others in the industry should heed this as a warning.
"Hotel companies must immediately review all information on their corporate websites and apps, and strictly abide by Chinese laws and regulations to firmly stop such incidents from happening again," it said. "Officials must ... severely punish violators."
Marriott was also chastised after one of the firm's social media accounts "liked" a post made by a group supporting a separatist Tibet.
Marriott apologised profusely. "Unfortunately, twice this week, we had incidents that suggested the opposite," said Arne Sorenson, president and CEO of Marriott International in a statement.
The company said it had corrected a survey sent to members of its loyalty programme that labelled certain regions, including Tibet, as countries, and was conducting a full review of its Chinese website and apps.
Marriott is also investigating the "careless 'like'" by one of its official social media accounts of a pro-Tibet tweet that suggested its support for the position.
"Nothing could be further from the truth," Sorenson said.
Marriott said it would take disciplinary action, which could involve firing the people involved. It also promised to work with Chinese authorities on their investigation.
China's cyber regulator has demanded meetings in Shanghai with two top regional executives from the American hotel chain and ordered the company to "conduct a comprehensive self-review and rectification".
Marriott has "seriously violated China's relevant laws and regulations and hurt the feelings of the Chinese people," it said.
Sorenson has previously described China as his firm's biggest market.The hotel conglomerate operates 6,200 properties in 125 countries around the world. It operates well over 100 locations in the Greater China region.
The website of Starwood, which is part of Marriott, was also taken offline in China.Chinese media is reporting that some travellers are cancelling Marriott reservations in response.
China is usually quick to respond to any actions or statements it deems supportive of separatist movements, especially related to Tibet and Taiwan.
Authorities also shut down Marriott's Chinese mobile phone app as part of its punishment for the Mandarin-language survey. But having being closed earlier, the app now appears to be functioning, according to CNN.