A Chinese government official says China will turn down any request for the return of ancient Japanese treasures given in tribute to past Chinese rulers.

Beijing's Palace Museum has several hundred items dedicated by the Ryukyu Kingdom, now Japan's prefecture of Okinawa, to ancient Chinese emperors.

He was responding to Japanese media reports that officials in Okinawa had asked Japan's new ambassador to China, Yuji Miyamoto, to "return the Ryukyuan treasures to their hometown".

"This is impossible if they are referring to articles given as tribute to emperors during the Ming (1368-1644) and Qing (1644-1911) dynasties by the Ryukyu Kingdom, a dependency of China at that time," said Zheng Xinmiao, the Place Museum curator and Vice-Minister of Culture.

"We would like to be of assistance if the people of Okinawa wish to borrow these treasures for exhibition," said Zheng, adding China had not received a formal request in this regard.

The Palace Museum house hundreds of pieces of "treasure from Ryukyu", such as fabrics, paintings, books and lacquerworks.

"We organized an exhibition of these items in Okinawa once and that is the only time they have been abroad for show," Zheng was quoted by Monday's Beijing News as saying.

Historical records show the Ryukyu Kingdom formally became a dependency of China in the 1300s and the association lasted nearly five centuries before Japan claimed it as a prefecture in 1879.