Hurricane Dean's rampage over Mexico's Caribbean coast last week unearthed three rusted 18th century cannons that had lain buried under a sandy beach for decades.

The cannons, around 1.80 meter (5.9 feet) long, were spotted poking through the sand on a beach near the arty resort of Tulum after Dean hit on August 21, Mexico's National Institute of Anthropology and History (INAH) said on Wednesday.

Believed to be from a shipwrecked European galleon, the badly corroded cannons will be put back in to the sea to protect them from faster corrosion onshore and for scuba divers to enjoy, it said.