The daughter of a Hong Kong-based bookseller who was secretly detained in China says he has been taken away by Chinese authorities again after being released into house arrest last October.

Angela Gui told Radio Sweden on Monday that her father, Gui Minhai, was on a train with two Swedish diplomats when police officers seized him.

Gui, a Chinese-born Swedish national, ran a Hong Kong publishing company specializing in gossipy tales about high-level Chinese politics when he disappeared from his Thai holiday home about two years ago and later turned up in Chinese custody.

Gui was freed in October but his daughter told the station he remained under surveillance.

She said he was traveling to Beijing to see a Swedish doctor about neurological symptoms he developed while in custody.