Bones found at a property in Rome belonging to the Vatican do not belong to two girls who went missing in the 1980s.

The bones were found at the end of October in the basement of the caretaker's lodge at the Apostolic Nunciature in Rome.

The discovery gave rise to speculation that they were those of Mirella Gregori and Emanuela Orlandi, two young girls who went missing within weeks of each other in 1983.

Orlandi was the daughter of a Vatican employee and lived in Vatican City with her family when she mysteriously disappeared in June 1983.

The two girls, who were both 15 at the time, have never been found but speculation has persisted that their disappearances are linked.

Zenit news agency reports that an insider in the case of the newly discovered bones has discounted any link with the missing girls after initial analysis revealed the remains are over 50 years old.

Giovanni Arcudi, Professor of Legal Medicine at Tor Vergata University, was appointed by Rome's Procurator General to examine the bones.

According to Zenit, he said in an interview with InBlu Italian Catholic Radio on Monday that the bones belong to a man and date back to before 1964.

The Italian authorities became involved in the investigation after the Holy See reported the discovery, Professor Arcudi said.

The remains were discovered during work on an annex to the Vatican compound located close to Rome's famous Villa Borghese museum.

The investigation continues.