A Picasso worth 25 million euros ($27.4 million) and considered a national treasure by Spanish authorities - who had barred it from being exported - has been seized from a boat docked in Corsica, French authorities said on Tuesday.

An attempt to export the painting, Head of a Young Woman, to Switzerland on Thursday "drew the attention of French officials", the country's customs authorities said, with officers on the French island boarding the vessel the next day.

The ship's captain could only present two documents regarding the work of art, one of which was a Spanish court judgment in May labeling the painting a work of art and ordering that it not be taken out of the country, French officials said in a statement.

The painting, which French customs said is valued at more than 25 million euros, is owned by Jaime Botin, a well-known Spanish banker whose family founded the Santander banking group.

The 79-year-old, who was formerly the banking giant's vice-chairman, was not aboard the vessel, which is owned by the bank and flying a British flag, a customs authority spokesman said.

According to the spokesman, the export request was also not in Botin's name.

An export request was filed for the painting in December 2012 to move it to London, but was opposed by Spain's culture minister.

This year, a Spanish court sided with the authorities and declared the work of art "unexportable" on the grounds that it is of "cultural interest" and could not leave the country.

French customs officials are now awaiting an official Spanish request to recover the painting.