Premier Silvio Berlusconi was rapped on Wednesday by Catholic bishops, who joined in protests over the centre-right leader's use of a vulgar word to describe opposition voters.
Bishops' daily Avvenire commented that "we thought we'd heard it all... From a head of government, one expects responsibility and style, always - without lapses and without excuses".
The incident occurred on Tuesday when Berlusconi, who is hoping to be returned to power in Italy's April 9/10 general elections, said that "I have too much respect for the intelligence of Italians to think they would be such 'coglioni' as to vote against their own interests - pardon my rough but effective language".
'Coglioni' literally means 'testicles' or 'balls' but in this context it is an insult that could be translated as 'asshole' or 'moron'.
Green leader Alfonso Pecoraro Scanio said that "Berlusconi must apologise to Italians for yesterday's offensive phrase, which is unacceptable for somebody who is head of government... By branding millions of citizens 'coglioni', Berlusconi has once again brought ridicule on Italy in the international press. He should be ashamed of himself".
Thousands of ordinary centre-left voters also staged protests, rallying in parts of the city centre on Tuesday carrying placards saying 'I am a coglione' while other's have shared their photos with the stamp - "Conglione? No. Orgolione" - "Asshole? No. I'm Proud"
In Naples, opposition sympathisers immediately appeared on the streets wearing T-shirts bearing the slogan, 'Better coglioni than Berlusconi'.