Giancarlo Galan, the head of a parliamentary culture commission, on Sunday lamented the latest collapse at the archaeological site near Naples.
Italian media reported that Saturday's rainstorm provoked the partial collapse of a wall around a necropolis and caused some stones to fall at The Temple of Venus.
Despite the damage, Pompeii remained open to tourists Sunday. But its offices were closed and further details were not immediately available.
Last year, the Italian government appointed a special official to ensure that European Union and Italian funds were properly spent to repair and protect Pompeii.