India on Tuesday said that it had registered a strong protest with China over what it said was the arbitrary detention of an Indian citizen at Shanghai Airport.

Indian media reported that a UK-based woman holding an Indian passport was stopped by Chinese authorities during a layover in Shanghai on Friday last week and told that her Indian passport was invalid, as she was born in the eastern state of Arunachal Pradesh.

Beijing says Arunachal Pradesh, which it calls Zangnan, is part of China, a claim that New Delhi has repeatedly dismissed.

The woman, Prema Wangjom Thongdok, said she was not allowed to board her onward flight to Japan and was held for 18 hours, Indian media reported.

"Chinese authorities have still not been able to explain their actions, which are in violation of several conventions governing international air travel," Indian Ministry of Foreign Affairs spokesman Randhir Jaiswal said in a statement.

A Chinese Ministry of Foreign Affairs spokesperson said that the checks had been carried out in accordance with laws and regulations.

Jaiswal said that India had taken up the incident "very strongly" with China.

India and China share a 3,800km border that is poorly demarcated and has been disputed since the 1950s.