The Federculture association's report said the cash-strapped city of Rome had reduced spending on culture to 2.23 percent of its budget in 2012 from 4.33 percent in 2002 and would cut transfers further by up to 50 percent this year.
The national state budget for the culture ministry was also being reduced to €1.4 billion a year for 2014-2016 from €1.5 billion in 2013.
Spending on upkeep of Italy's priceless cultural heritage has meanwhile dropped to 75 million euros for 2013, compared to 165 million euros in 2008, it said.
"The situation is disturbing," Roberto Grossi, the head of Federculture, which groups public and private culture workers, told the Il Messaggero daily.
"If we turn off the lights on culture, cities are emptied of tourists, they become poorer," he said.
Grossi said the legal measures to allow private sponsorship of cultural treasures were not working properly and in any case private donations have fallen sharply during Italy's longest post-war recession.
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Sponsorships have dropped by 38 percent since 2008 and donations from bank foundations - once a huge source of revenue - have fallen by 40 percent.