Colombian naval officials monitoring a sunken Spanish ship laden with treasure have discovered two other historical shipwrecks nearby, President Iván Duque has announced.

The San José galleon was sunk by the British in 1708 near Colombia's Caribbean port of Cartagena.

The wreckage was located in 2015.

It has been described as the holy grail of shipwrecks, as the ship was carrying one of the largest amounts of valuables ever to have been lost at sea.

A remotely operated vehicle filming the wreckage has now discovered two other nearby wrecks - a colonial boat and a schooner thought to be from around the same period as Colombia's war for independence from Spain, some 200 years ago.

"We now have two other discoveries in the same area, that show other options for archaeological exploration," navy commander Admiral Gabriel Pérez said. "So the work is just beginning."

The new images offer the clearest view yet of the treasure aboard the San José - including gold ingots and coins, cannons made in Seville in 1655 and an intact Chinese dinner service.

Archaeologists are working to find out the origin of the plates based on inscriptions, officials said.

Ownership of the wreck has been the subject of a long-running legal row.

Spain says the ship and treasures are a "ship of state" as it belonged to the Spanish navy when it was sunk and is protected as such by United Nations regulations.