The ruling centre-left Democrat party's candidate for governor of the southern Campania region, Vicenzo De Luca, was among 17 politicians deemed unfit for office by the Italian parliament's anti-mafia commission on Friday.
De Luca has said he will sue the commission chair Rosy Bindi for defamation and has also challenged her to a debate, his staffers said.
De Luca, a former mayor of the southern city of Salerno, who is credited with regenerating the city, was this year convicted by a lower court of abuse of office in the handling of a local incinerator project while mayor.
De Luca is the only Democratic Party member on the 'unelectable' list although three other politicians are from lists backing his bid for Campania governor in regional elections being held on Sunday.
All 17 politicians on the parliamentary anti-mafia commission list are from the Campania and neighbouring Puglia region and most are from centre-right parties.
Bindi said the commission screened 4,000 candidates in Sunday's regional elections, which are taking place in over 1,000 localities in seven regions across Italy.
Some 17 million Italians are eligible to vote in the polls, which are the first major test of support for Italy's centre-left premier Matteo Renzi since he triumphed in European elections a year ago.
The January court ruling against De Luca handed him a one-year suspended prison term and an 18-month ban from holding public office although under Italy's judicial system, he can take his case to an appeals court and ultimately the supreme court before receiving a definitive sentence, a process likely to take years.
