Colombia has found the wreck of a Spanish galleon that sank off the coast of Cartagena and is thought to be laden with emeralds and gold and silver coins, President Juan Manuel Santos says.

More details were to be provided at a news conference on Saturday, Santos said from his Twitter account.

An example of a Spanish galleon. This is a drawing of the galleon Conception.

The San Jose sank in 1708 in the Caribbean Sea close to the walled port city of Cartagena. It was part of the fleet of King Philip V as he fought the English during the War of Spanish Succession.

"Great news! We have found the San Jose galleon. Tomorrow we will provide details at a press conference from Cartagena," Santos tweeted.