Family members and lawyers said on Wednesday they have sent letters to Italy's government and president demanding reparations for what they say was a violation of the Savoys' human rights.
Government officials and politicians dismissed the request, saying Italy should be the one seeking damages for the monarchy's support of Benito Mussolini's fascist dictatorship and its conduct during the war years.
Victor Emmanuel, the son of Italy's last king, and his family returned to Italy in 2002.
Their exile was the result of a 1946 referendum in which Italians chose to get rid of the monarchy. Two years later, the new constitution barred the last king, Umberto II, and his male descendants from Italy.
That provision, which was overturned in 2002, violated the European Convention on Human Rights that bans inhuman and degrading punishment, Victor Emmanuel's son, Emmanuel Filiberto, told private TV news TG5.
"We have asked our lawyers to contact the Italian government to examine the problem," he said. "It is well known that from 1948 on Italy went against the Convention on Human Rights."
Emmanuel Filiberto was born in 1971 in Switzerland, where the family spent most of the exile.
Calvetti told The Associated Press he would take the case to the European Court of Human Rights and ask Italian courts to award the family money and return property that was seized after the war, including the Quirinale, the presidential palace in Rome. He said anything gained from the actions would be donated to charity.
Carlo Malinconico, secretary general of Prodi's office, rebuffed the request in statements to the Italian media.
"Nothing should be paid," he told the Corriere della Sera daily. "It's the state that should ask the Savoys for reparations for their responsibilities in past historical events."
Then-King Victor Emmanuel II is largely blamed for his ties to Benito Mussolini and for backing fascism's persecution of Jews and its alliance with Hitler.
The king, father of Umberto II and grandfather of Victor Emmanuel, did eventually turn against Mussolini in 1943, deposing the dictator and surrendering to the Allies. But in what was widely considered a betrayal of Italy, the royals then fled Rome for the Allied-occupied south, leaving large parts of the country in Nazi hands until the end of the war.