A 200-year-old shipwreck with a cargo including gold ingots worth around R120 million has been found about 10km off Cape Agulhas.

The wreck of the Brederode, partially buried in the sandy seabed, contains thousands of historical artefacts, which will be excavated early next year by a team of archaeologists and divers in a hi-tech underwater operation that will cost around R18 million.

Most of the items recovered will be auctioned.

The wreck was found at a depth of 65 metres in June last year by Cape Town-based salvage company Aqua Exploration, but the find was kept under wraps until a legal document had been drawn up between the salvage company, the SA Maritime Museum and the National Monuments Council.

Aqua Exploration and an internatinal salvage company, Hallstrom Holdings, will get rights to the cargo, while the SA Maritime Museum will get the ship's remains, personal effects of the crew and a sample of each type of cargo found.

The Brederode, owned by the Dutch East India Company, sank in 1785 on her return voyage from China and Indonesia while carrying a cargo of porcelain, tin, spices, tea, satin and gold in small Chinese ingots.

Archaeologists have called the wreck "a small time-capsule" as it has lain undisturbed for more than two centuries. The ship apparently sank after she hit an uncharted reef off Agulhas.

Eighty of the crew got to shore in boats, but 12 went down with the ship.

Archaeologists said on Wednesday it is likely that the remains of the 12 crew would be found in the wreck. If so, they would be brought to the surface for examination and would later be returned to the Brederode, which has been their grave for 214 years.

A report written by Brederode's captain, Gottlieb Mulder, says that around 1am on May 13 "the ship hit a reef without anyone on duty having seen any surf or breakers in the sea. The ship struck sorely four times ... The rudder was gone and suddenly there was six feet of water in the hold."

They got the pumps going but the water continued to rise. They then tried to turn the sinking ship towards the shore in the hope of running her on to a sandy beach so that they could salvage the cargo, but were unable to do so.

They abandoned ship before dawn. With daylight, people were seen signalling from the ship; not everyone had made it into the lifeboats.

They could not be rescued because heavy breakers had left the two lifeboats high on the shore and people on shore could not get them back into the water.

Cape Town diver Charlie Shapiro of Aqua Exploration said on Wednesday that he and his team had been searching for the Brederode for 16 years. He had combed archives in the Netherlands, UK and South Africa, and had found details of the ship's cargo and how she had sunk.

"We knew she would be a difficult wreck to locate because she had hit an uncharted pinnacle and then she had drifted," Shapiro said.

In 1991 a Cape Agulhas trawler fisherman, who has since died, told one of the divers, Andre Hartman, that his nets had once snagged on something and that when he had pulled his nets up, he had found a wooden pulley block which he assumed was from a wreck.

At last the salvors had an approximate position for the Brederode. A sonar scan yielded an underwater image, but they could not say conclusively that it was a wreck.

Shapiro contracted several survey companies between 1991 and 1997 to help with a positive identification, but they were unsuccessful.

In 1998 a shipwreck explorer based in Singapore, Sverker Hallstrom, joined up with Aqua Exploration. With his sophisticated equipment he was able to identify it as the Brederode. The ship's bell was lying next to the wreck, as were two bronze cannons and items made of porcelain and tin.

Archaeologists hope that most of the cargo will be intact in the hull. The excavation will be funded by the salvors, who also hope to raise sponsorship for the operation.

Asked what the chances are of finding the valuable gold ingots, one of the archaeologists replied: "We don't know. It's possible the captain took the gold with him.

"He did have six hours to get off the ship."