A toddler has died and his twin brother is fighting for his life at a Rome hospital after a botched home circumcision carried out at a migrant refuge on the outskirts of the city.

Italian police and local prosecutors have opened a murder investigation into the death of the boy who reportedly died of severe blood loss on Saturday when the procedure went wrong.

He and his brother, who have not been named, were born in Italy in January 2017 to a woman of Nigerian origin who is believed to have sought asylum in Italy.

The operation took place in a welcome centre with nine apartments provided by the nonprofit organization Arci and the local council in the town of Monterondo, a suburb of Rome.

"We are shocked to learn of the death of a child and the serious condition of his twin in Monterondo,” Arci’s Rome branch said in a statement published on its Facebook page on Sunday.

“The two children are hosted in a welcome centre that Arci has run with Monterotondo Council since 2009. It is a tragedy that leaves us speechless! We are anxiously awaiting a medical update on the second child.”

Italian media reports said police were questioning the doctor, also believed to be of Nigerian origin, who had carried out the operation and had called for emergency assistance when the child began bleeding profusely. The baby's twin brother is in intensive care at a Rome hospital.