Volcanic crater
(File photo) The boy apparently slipped after entering a prohibited area at the Solfatara Crater in Pozzuoli. Getty

Three family members including an 11-year-old boy have died after falling into a volcanic crater in Italy.

Police believe the child along with his two parents died after entering an closed off area at the Solfatara crater in Pozzuoli, near Naples.

It is thought the parents, believed to be in their 40s, fell into the pit after attempting to retrieve the boy when he had wondered into a forbidden area and slipped.

It is not immediately clear if the family died as a result of being overcome by gases or were killed as the result of an explosion of super-heated mud.

A seven-year-old boy who was a member of the same family was located nearby but remained outside the fenced-off area. According to Repubblica, the seven-year-old is currently being looked after by a psychologist.

A Campi Flegrei park official told AFP. "We are still trying to understand what happened. They crossed the security barriers and fell into the hole".

Heavy rain in the area may have played a part in creating more holes on the volcanic crater's surface.

The crater is located in the Phlegraean Fields and is hugely popular with Italian school children and tourists from around the world.

There are signs located all around warning people not to breach the security fences and to stay away from the openings in the Earth's crust that emit steam and gases which can be as hot as 160C 320F).