The man, who is in his 50s, has been reported to police in the northern city of Biella, regional governor Alberto Cirio said, adding that the silicone on the prosthetic arm looked "very similar" to real skin, Reuters reports.
"(However) the colour and touch raised the suspicion of the health worker, who asked him to show the whole arm," Cirio said.
The man subsequently tried to persuade the nurse to turn a blind eye but instead, she reported him to the police for fraud, according to the local media.
"The incident would border on the ridiculous, were it not for the fact that we are talking about an extremely serious act," Cirio said in a post on Facebook.
He described the ploy as "unacceptable faced with the sacrifice that our entire community has paid during the pandemic, in terms of human lives, the social and economic cost".
Ansa news agency reported that the man, who has not been named, worked in the health sector and had been suspended from his job because he had refused to be vaccinated against COVID-19.
But the incident may not have been a one-off. Italian outlet La Republicca pointed to a message on social media that may have been written by the man.
The paper quoted a Twitter post featuring a silicone male chest half-body suit, complete with fake arms and neck, that was on sale on Amazon for €488.
"If I go with this, will they notice? Maybe beneath the silicone I'll even put on some extra clothes to avoid the needle reaching my real arm," the Twitter user reportedly wrote.
The incident comes as Italy looks to clamp down impose tougher for the unvaccinated.