The cities at risk of running out of money include Naples, Palermo in Sicily and Reggio Calabria, on the toe of the Italian boot, according to the Italian press.
"The situation is becoming worse by the day," said Graziano Del Rio, the president of a national association of municipal councils.
The warning came just days after Mario Monti, the prime minister, expressed fears that Sicily, which has a high degree of fiscal autonomy, was on the brink of a default.
Cities and towns in southern Italy have for years been plagued by mismanagement, corruption, the wasteful use of EU funds and infiltration by the Mafia. But the "black list" of cities at risk also includes some in the north of Italy such as Alessandria, in the Piedmont region.
Italy's regions face "a serious situation", said Annamaria Cancellieri, the interior minister, although she downplayed concerns that Sicily would be forced to default.