Experts combing the remains of the ship said they did not expect it to contain treasure, but so far they have discovered several canons and well-preserved earthenware jars that were probably used to store olive oil.
The remains of the galleon were found on a building site close to the shores of the River Plate and archeologists from Buenos Aires city government think the boat was probably shipwrecked some 300 years ago.
"You can see it's very old and we think it dates from the 1700s, although it's also possible that it's from the 1600s," said archeologist Marcelo Waissel.
"I don't think there's any treasure, but what there will be is a nice collection of artefacts," he told local television, adding it was the first time such a discovery had been made in the city.
Workmen were helping the investigators retrieve artefacts from the site and Waissel said the city government would ensure that the discovery was preserved even though the construction of the building will continue.
Last Mod: 31 Aralık 2008, 12:02
"The building's going to go ahead and the area will be protected so the archeologists can carry on recovering bits of what's been found," Buenos Aires Mayor Mauricio Macri told reporters at the site in the Puerto Madero district, an area of former docks and reclaimed land that has been redeveloped with offices, apartments and upmarket restaurants in recent years.