The court ruled that Spain does not have to reimburse Odyssey for the cost of preserving the treasure [AFP]

A US federal judge has ruled that a Florida-based company that found sunken treasure from a 19th century warship must return 594,000 silver and gold coins to the Spanish government by next week.

The 17 tonnes of coins and other items are valued at more than $500m, making it the biggest sunken treasure recovery in history.

The ruling in the city of Tampa on Friday also said that Spain does not need to reimburse the deep sea recovery firm, Odyssey Marine Exploration, for its costs of preserving and storing the treasure.

Odyssey found silver and gold from the galleon Our Lady of Mercy in 2007, which a British fleet sank in 1804 off the coast of Portugal. The ship was returning to Spain from Peru.

The company shipped the silver and gold to a Tampa warehouse while it fought lawsuits with the Spanish and Peruvian governments over property rights to the treasure.

Last week, the US Supreme Court refused to overturn a lower court decision saying the treasure belonged to Spain.

"The treasure must be accessible to Spain on Tuesday the 21st and by February 24th it has to be transferred to Spain," an official at the federal court in Tampa told the AFP news agency.

Melinda MacConnel, Odyssey's general counsel, said the Spanish government might have won a legal battle but they hurt their chances of ever again recovering sunken treasure.

"Spain has been very short-sighted in this case," MacConnel said in a statement.

"They have not considered the high cost of storage and conservation of these coins, but more importantly they have failed to consider that in the future no one will be incentivized to report underwater finds.

"Anything found with a potential Spanish interest will be hidden or even worse, melted down or sold on eBay."

Source: Agencies