Dubbed the "mini-Forbidden City" complex within the Forbidden City, the newly restored Juanqinzhai in Qianlong Garden's will be opened to the public next year, a spokesman of the Palace Museum said on Monday.

Juanqinzhai means "Lodge of retirement" and was designed by China's longest reigning emperor, Qianlong, for private use following his retirement in 1771.

At the time China was one of the world's largest and most prosperous nations. Constructed with the finest materials and artistry available to the Qing Dynasty (1644-1912), it is adorned with bamboo-threaded flooring, white-jade cartouches and luxurious wall decorations.

Largely in a state of disrepair, Juanqinzhai became the subject of an international restoration effort, organized by the world Monuments Fund (WMF) and the Palace Museum, in 2001.

The $3 million project is the first phase of a 12-year multimillion-dollar project to restore the entire complex.

Liu Chang, a professor of the architecture department of Tsinghua University, said: "We have accumulated precious knowledge and developed the best approaches in order to adapt the building with contemporary climate control, lighting, and museum exhibition technologies."

The lodge was as fragile as the art it contained, but is now in a condition to protect its precious contents, he said.