Italian authorities have suspended 16 prison guards who allegedly celebrated the suicide of an inmate with a series of offensive posts on social media.

Numerous distasteful remarks appeared on the Facebook page of a jail warden union, Alsippe, as comments to a news article link regarding the death of Ioan Gabriel Barbuta, a 39-year-old of Romanian origins who was serving a life sentence for murder in Milan's Opera jail.

"One less," a user wrote. "Great, I hope he suffered," said another.

"They should provide them with more ropes," a third commented. "One less Romanian who killed an elderly man. Hurrah!" rejoiced another.

Most of the comments were made by accounts that appeared to be controlled by members of Italy's prison police force.

One had a man in uniform as profile picture while others listed policeman or prison guard as profession.

The post was picked up by local media, sparking nationwide outrage.

Several lawmakers from the left condemned the incident and said they will question Justice Minister Andrea Orlando on the issue. In turn, Orlando summoned the head of Italy's prisons administration (DAP) Santi Consolo, saying the prison guards' behaviour, if confirmed, was "unacceptable".

Consolo said they were probing that the comments' authors were actually prison guards. Sixteen officers were suspended as a precautionary measure, pending further investigation, he said.

The secretary of a separate jail warden union Donato Capece also slammed his colleagues.

"Cheering the death of an inmate is a despicable and shameful act," he said.

Only Matteo Salvini, the leader of the xenophobic Northern League, expressed solidarity with the wardens involved, saying that he didn't justify their action but knowing their work conditions he understood them.