MADRID Spain has sent an armada into waters around its coasts to seek out hundreds of shipwrecks in an attempt to head off US treasure hunters accused of plundering Spanish property from the seabed.

Over the past month, more than 100 suspected shipwrecks have been located by the Spanish navy in the Gulf of Cadiz, considered one of the world's richest hunting grounds for underwater treasure.

Dozens of Spanish galleons returning from the colonies in south American in the 16th, 17th and 18th centuries are believed to have sunk in waters around Cadiz.

British Royal Navy warships and other British vessels may also be among the wrecks the Spanish navy says it has located.

Between 500 and 800 ships are thought to lie at the bottom of the Gulf of Cadiz.

Three Spanish navy vessels, including two minesweepers, and 100 navy personnel are devoting two months to the project, which will end in mid-November.

Spain is in the middle of a legal battle with the deep-sea treasure hunters Odyssey over treasure the US company has recovered from the seabed. It wants to avoid a repeat of the saga that began in 2007 when Odyssey salvaged an estimated $500m in silver coins and artefacts from what Spain claims was a Spanish galleon. The treasure was landed at Gibraltar and then flown out to the United States.

A US court ruled last year that the find belongs to Spain, but Odyssey appealed and still has the treasure. It was due to submit its appeal at a US court on Thursday.

Odyssey has also mapped sections of the English channel seabed.—Dawn/The Guardian News Service