A man has been expelled from Croatia and fined after he punched a Mediterranean monk seal, one of the world's most endangered species, reports said.

Dozens of tourists and locals had gathered on the beach at Gortan bay on the northern peninsula of Istria - a protected habitat for the monk seal - when a 56-year-old Macedonian man suddenly rushed forward and started punching the seal.

The seal was not injured and made good its escape from the beach into the sea, state news agency Hina reported.

The man, whose name was not revealed, was sentenced to pay a €210 fine and is expelled from Croatia for five-year period for "breaching the Law on Nature Protection," Hina said.

The Mediterranean monk seal is one of the rarest sea animals in the world, with less than 600 individual mammals found in the wild, most of which are found in parts of the Mediterranean Sea and the Atlantic ocean.

The rare seal was  believed to have been extinct in the Adriatic for decades, but several animals have appeared in the waters around northern Croatian port of Pula since 2005.