A 12-year-old Swiss boy died after a tunnel he dug in sand dunes with his two brothers at a beach in Spain collapsed around him, police and local officials said.

Paramedics tried but failed to resuscitate the boy after he was pulled out of the sand at the beach at Castello d'Empuries on Friday afternoon, the mayor of the town, Salvi Guell, told Catalunya Radio.

"Sometimes children do not notice the limit between fun and risk and it is adults who should be on the lookout," he said.

The boy, whose identity was not revealed, was on holiday at the beach, located 125 kilometres (75 miles) north of Barcelona near the border with France, with his family.

His two brothers, aged eight and 13, did not immediately notice that the tunnel has collapsed and it was a lifeguard on duty at the beach who first sounded the alarm, police said.

The Castello d'Empuries beach, popular with windsurfers, has huge dunes which are created by strong winds that regularly blow in the area.