"The commission president has decided to ban wine during the finance commission meals without informing anyone," Daniel Sormani, a representative of the populist Geneva Citizens' Movement wrote in a letter to his colleagues cited by the Tribune de Geneve (TdG).

The decision "shocked the vast majority of the commission", he said, demanding a reversal.

Commission president, Socialist Alberto Velasco, meanwhile insisted the move was necessary, describing how insults began flying as the bottles on the table emptied.

The 15-member commission meets between 5:30pm and 10pm over a warm meal and has until now shared two bottles of wine.

While the quantities are modest, Velasco told TdG that half of the commission did not drink, so the remaining members each got a few glasses.

We are dealing with large amounts of money," he said, insisting that "by lowering the alcohol levels ... we will be more deserving of the citizens' confidence".