The architect responsible for works, Oreste Albareno, tried to reassure the workers by spending a night with them but ended up also being convinced the museum was haunted, Italian daily Il Mattino reports.
The builders happened to be working in the museum over night and they heard ‘soul-piercing screams’ and felt the temperature drop dramatically only to suddenly rise again. Some of the workers claimed to have seen a real ghost.
Mr Albareno told the paper that he had managed to take a photo of what he believed to be a ghost on his mobile phone. 'It shows a little girl but there was no little girl on the site,' he said.
'None of the staff took a daughter with them - it is a secure locked site so there was no way the child could have sneaked in.'
The case has been likened to the the film Nights In the Museum, where the exhibits come to life at night after the museum closes because of the power of an ancient relic displayed on the premises.
The National Archaeological Museum's collection includes artifacts from the Greek, Roman and Renaissance.
Ms Sampaolo added: 'I don't know what is causing what the builder's claim they have seen and we do have many ancient artifacts with mysterious backgrounds but at the end of the day I want it to stop.
Now this could be a story of the highest paranormality. Or, these crafty Italians had enough of work and decided to call it a night, not realising that they would start an international ghost hunt. We have to say though, they have their story straight.
'I want people to talk about our museum because of the exhibits and not the ghosts.'
Paranormal experts are due to arrive at the museum in September to investigate the claims.