A fake Chinese identity card and passport has left a South Korean national in a state of jurisdictional limbo.

The man was sent back to China on Thursday by South Korean authorities who viewed him as an "unauthorized Chinese," and he cannot travel around the country, according to Pudong International Airport immigration authorities.

The South Korean citizen told the Shanghai police that he had bought a Chinese ID card and the passport of a man surnamed Du as he believed that this would make it easier for him to buy an apartment in Qingdao, Shandong Province, where he works. Police said the South Korean man actually believed that he had valid Chinese documents. The man entered China through Qingdao in January 2004 and worked as a computer engineer in a company. In 2005, he paid 50,000 yuan (US$7,315) to a Chinese agent to buy the passport and ID card.

But early this week, he decided to travel to Cheju Island in South Korea with a friend and thought he could use his Chinese identify papers to get through the immigration.

However, the two men were refused entry by the South Korean immigration authorities, as they could not give proper information about their place of stay and itinerary in the country.

Immigration officials stamped him as "unauthorized Chinese" and "repatriated" the two men.

Although Cheju Island now allows visa-free sightseeing trips for people from China, South Korean authorities have tightened immigration supervision at the airports. According to the airport police, many Chinese are now being refused entry into South Korea.

But when he was being sent back, the man did not dare reveal his real identity as a citizen of South Korea. Immigration officials did not reveal how the man would be dealt with.