Beijing's Palace Museum, the Forbidden City, will keep the authenticity of all structures intact in maintenance work and security installation done on the relics, Shan Jixiang, the museum's curator, said on Thursday.

"We will conduct scientific design and feasibility studies before we repair a building, so that the relic remains intact and authentic," said Shan, who is also a member of the National Committee of the Chinese People's Political Consultative Conference.

Shan pointed out that preservation work at the Palace Museum will take heed of day-to-day maintenance as well as major repairs.

A project to upgrade the museum's security system to better protect the relics is under way, Shan said.

The project, which began in 2009, is scheduled for completion in 2013. By the end of 2011, about 60 percent of the work had been finished.

The Palace Museum was criticized after a theft in May that resulted in a loss of 1.65 million yuan ($261,690) in artworks.

"The alarm, a major part of the security system, was long functionally obsolete. Now, we are upgrading the alarm system with the first-rate equipment," Shan said.

"Judging from the results of the upgrades already completed, the security will greatly advance," Shan said.

"Meanwhile, we will try to inconvenience visitors as little as possible as we upgrade the system."

The Palace Museum had 14.2 million visitors last year, taking in 650 million yuan in ticket sales.

"About 60 percent of the Palace Museum is expected to open to the public by 2020 to balance the pressure from the increasing number of tourists and the preservation work," Shan said.

Currently, around 30 percent of the museum is open to the public.

Shan said some parts of the museum, such as the Yuhua Pavilion, will be presented to tourists in the form of digital show and other parts, such as Emperor Qianlong Garden, may open to a limited number of visitors to protect relics. However, the methods of opening more parts of the museum are still under discussion.