Archaeologists estimate that there are up to 70,000 relics on the ship, which some cultural experts estimate are worth about $100 billion.

The two-month operation by Guangzhou Salvage Bureau under the Ministry of Communications in collaboration with a British salvage company will cost about 100 million yuan ($12.9 million).

Dating back to the early Southern Song Dynasty (1127-1279), the wooden merchant vessel, accidentally found off Yangjiang waters of Guangdong in 1987, was the first ancient ship discovered on the "Marine Silk Road" of the South China Sea and so was aptly named Nanhai I, meaning South China Sea No 1.

Lying on the seabed 20 meters below the surface, Nanhai I is 25 meters long and weighs an estimated 4,800 tons, the largest cargo ship discovered from that period so far.

The ship was located using global positioning system (GPS) technology.

"It is unprecedented in underwater archaeology both at home and abroad," Kuang Jingming, deputy director with the Guangzhou Salvage Bureau of the Ministry of Communications, said.

Such salvage operations would usually recover relics first, followed by the vessel, Kuang said.

However, the operations team will use different tactics with Nanhai I.

"In order to better protect the precious relics on Nanhai I, and gain essential historic information, we plan to salvage it with the silt that covers it," he said.

The two meters of silt have helped protect the treasures and the ship, but at the same time presented archaeologists with significant challenges in recovering the boat, according to Zhang Wanxing, a member of China's national underwater archaeological team.

Measuring, drawing and photographing the relics were almost impossible. Drainage of the silt in the sea would cause damage to the porcelain on the ship, Zhang said.

In order to prevent damage to the relics caused by the recovery process, the ancient ship wrapped in silt will be put in a huge glass pool, in which water temperature, pressure and other environmental conditions will mirror the conditions of the sea bed where the ship has been for 800 years.

Green glazed porcelain plates, shadowy blue porcelains and other rare antiques have been found during the initial exploration of the ship.