By Isla Binnie
ROME (Reuters) - Italian Prime Minister Matteo Renzi's drive to reform one of Europe's most sluggish economies is being threatened by a sharp drop in voter support amid repeated corruption scandals and an immigration crisis.
Renzi's personal popularity has dropped 33 percentage points over the past year, according to pollster Demos, despite a tentative return to growth after three years of recession.
The fast-talking 40-year-old toppled his predecessor in a party coup 16 months ago, promising to put a new face on tired, corrupt Italian politics and shake up inefficient institutions.
Renzi's popularity surged and he was widely expected to dominate Italian politics for years to come. But after weaker-than-expected showings for his candidates in recent regional and municipal votes, internal opponents in his Democratic Party (PD) are becoming emboldened and the opposition is gaining ground.
Opinions differ on the significance of Renzi's reforms so far, which have focussed on the labour market and voting rules.
But with his approval ratings plunging and his parliamentary majority increasingly shaky, he is likely to find it harder to take on fierce opposition to his plans to overhaul the education system and a sclerotic public administration.
Demos said the PD, still Italy's largest party, now has 32 percent of voter support. A year ago, it won 41 percent in European parliament elections.
"We lost a few too many run-offs," Renzi said in a rare admission of defeat following last week's mayoral votes.
The PD lost second-round run-offs in five cities including Venice and the old left-wing stronghold of Arezzo in Tuscany - Renzi's home region - to right-wing candidates. In all
five cities its candidates led in the first round but were overtaken by voters uniting against them - a concern for Renzi who recently pushed through a similar two-round system for national elections.
CORRUPTION, IMMIGRATION
The seeds of trouble for Renzi were sown gradually.
The discovery last December of a vast system of corruption involving the PD-administered Rome government, on the heels of corruption scandals around Milan's Expo 2015 World Fair and Venice's flood barrier, continues to reverberate.
The latest twist in the so-called "Mafia Capitale" scandal revealed a gang was illegally profiting from running migrant camps of the sort which are groaning under the strain of the thousands of people who stream across the Mediterranean looking for a better life in Europe.
Public concern about the more than 50,000 arrivals this year alone is underlined by rising support for the right-wing Northern League party which says migrants spread diseases and leach resources from a fragile economy.
Meanwhile, the anti-establishment 5-Star Movement, whose fiery founder Beppe Grillo is taking a back seat to a new group of young media-savvy potential leaders, is closing in on the PD, helped by the graft scandals and attracting left-wing voters who feel Renzi is moving the party too far to the right.
According to Demos, the 5-Star Movement now has 26 percent of support, its highest level ever.
Renzi's plan to reform Italy's sub-standard education system, including a proposal to install school managers responsible for hiring, has sparked protests across Italy.
Senior PD member Michele Emiliano blamed the education plan for last week's poor electoral showing, saying: "All of that world campaigned against us. The reform cost us at least a million votes, which all went to 5-Star."
(editing by Gavin Jones and Dominic Evans)
