Experts are investigating the sea condition. [File photo]

The salvage of the sunken merchant ship Nan'ao No 1 was delayed on Saturday because of uncertain weather and sea conditions, archaeologists said yesterday.

"Once conditions permit, we will start salvaging the ship from the seabed," said Long Jiayou, director of the Guangdong provincial cultural relics bureau.

The centuries-old vessel is loaded with more than 10,000 pieces of antique porcelain from the Ming Dynasty (1368-1644).

"Compared with the salvage of the Nanhai No 1, pulling out the Nan'ao is more difficult given the complicated water conditions," said Long.

The Nan'ao is 27 m below the surface in waters off Nan'ao Island and covered by submerged reefs, which will hamper the operation, he said.

An opening ceremony for the salvage was held on Saturday in Shantou but no further operations were carried out.

The salvage is now scheduled for mid-December but experts are worried further bad weather could hurt their plans.

"Big ocean waves occur frequently in the Nan'ao sea area in autumn and winter," said Cui Yong, who is leading the salvage operation. "It is hard for us to pull the ship out of the sea. Instead we will just recover the relics for protection."

Divers can only work for about 30 minutes at a time because of the harsh conditions, he said.

The wreckage was found on May 25, 2007. For more than 800 days, archaeologists have been cleaning, mapping and filming the ship to prepare for the salvage.