* Democratic Party leader Bersani leads in first round
* Florence mayor Renzi main challenger
* Centre-left leading opinion polls for March parliamentary
(Releads with updated results, adds fresh quotes, details)
ROME, Nov 25 (Reuters) - Pier Luigi Bersani, head of Italy's
Democratic Party, will face his main rival Matteo Renzi in a
runoff next week to pick the centre-left candidate to fight to
succeed Mario Monti as prime minister following the first round
of a primary vote on Sunday.
With almost half the results counted, Bersani led with about
44 percent, ahead of Renzi, the youthful mayor of Florence, who
was campaigning as a moderniser, at around 36 percent, according
to party officials.
Both candidates have pledged to maintain the budget
discipline pursued by Monti's technocrat government and to
respect Italy's commitments to its European partners but say
they will encourage growth and will not blindly pursue austerity
"Pier Luigi Bersani has won the first round," Renzi, whose
result was better than polls had projected, told supporters late
on Sunday. He promised a "loyal" contest before the runoff vote
on Dec. 2.
"If we don't succeed, we'll lend a hand and together we will
try to win and finally close the ugly chapter left by the
centre-right," he said.
Nichi Vendola, the openly gay head of the left-wing Left,
Ecology, Freedom party was in third place with 15 percent, while
the remaining two candidates, Bruno Tabacci and Laura Puppato,
trailed far behind.
The outcome of the second round will remove one major
element of uncertainty dogging Italian politics ahead of spring
elections to choose a successor to Monti's government, which
took over after Silvio Berlusconi stepped down as prime minister
in November, 2011.
Monti has said he will not run in the next election,
expected in March, because it would destabilize the right-left
coalition that now supports him, though he has left open the
possibility of staying on if there is no outright winner.
The centre-left alliance is well ahead in opinion polls for
the election, although uncertainty over what electoral system
will be used in the ballot means it is unclear whether it will
be able to form a government without seeking allies from
Even so, the winner of the primary will be in pole position
to take over Monti's efforts to control strained public finances
and tackle a deep recession.
While the slick and dynamic Renzi, 37, is much more popular
across the general population, the 61 year-old Bersani's core
support among traditional PD party voters proved decisive.
"It's been a magnificent day. I'm extremely happy," Bersani
said as his lead in the vote became clear.
The unified front contrasts with deep divisions in the
centre-right over whether to stick with Monti's unpopular
economic policies. Support for Berlusconi's People of Freedom
party (PDL) has crumbled to less than half of what it recorded
in the last election in 2008.
Berlusconi, who has changed his mind several times over
whether or not to run in the election, added to the chaos facing
the PDL when he said on Saturday he was again thinking about
standing, throwing plans to hold a centre-right primary into
About 4 million party and non-party voters took part in the
centre-left vote, with queues forming at several outdoor polling
booths in cities across Italy.
Democratic Party (PD) officials said the strong turnout at
the poll, which was not restricted to party members, ensured the
next centre-left leader would be chosen in a fair and democratic
"With this level of participation and with very clear rules,
there is full and complete legitimacy," said PD deputy leader
Enrico Letta, a Bersani supporter. "The candidate for premier
who emerges from this election will be extremely strong."
While the PD has supported Monti's government in parliament,
neither Bersani nor Renzi think the former European Commissioner
should return as prime minister after the vote.
Business leaders have expressed strong support for a second
term for Monti, who has implemented a tough programme of
spending cuts, tax hikes and labour reform to cut the massive
public debt and restore economic competitiveness.
Monti, who has said repeatedly he would be ready to serve a
second term if needed, kept up a diplomatic silence about his
future on Sunday, saying only that he would consider what
contribution he could best make.
Protests on Saturday by tens of thousands of students and
workers from across the political spectrum highlighted the
levels of discontent among Italians grappling with the slump and
rising unemployment in the euro zone's third biggest economy.
Further complicating the national political picture is the
dramatic rise of the anti-establishment 5-Star Movement, which
is now second in opinion polls, and that around half of Italians
say they are either undecided or will abstain.
(Additional reporting by Silvia Ognibene in Florence and James
Mackenzie, Editing by Myra MacDonald and Paul Simao)