* Centre-left says Monti must stay in frontline
* Promises rapid reforms
* Says coalition with Monti could work and be stable
By Barry Moody and Giselda Vagnoni
ROME, Feb 19 (Reuters) - Italy's centre-left moved on Tuesday to quash fears that it will form a weak government after next weekend's election, saying it was committed to rapid economic reform and that outgoing premier Mario Monti must have a frontline political role.
"We are fully aware that inertia is not an option. We have no time to waste. Italy's problems are very serious and we cannot afford more recession or stagnation ... we need to deliver in terms of jobs, income, simplification," said Stefano Fassina, chief economic official in the centre-left Democratic Party.
Although markets have remained largely sanguine about the result of the Feb. 24-25 vote, there have been rumbles this week about the chances that it will bring instability or a weak, left-leaning government unable or unwilling to carry out the difficult reforms needed to make Italy competitive.
A centre-left coalition headed by Democratic Party (PD) leader Pier Luigi Bersani is widely expected to win the vote and the most recent polls show it 4-5 points ahead of Silvio Berlusconi's centre-right.
But pollsters expect Bersani to fall short of a controlling majority in the Senate, which has equal law-making powers to the lower house, forcing it to seek support from Monti's centrists and raising the spectre of a government split by disputes.
Fassina, who comes from the PD's left-wing, dismissed these fears and the suggestion that Monti, the technocrat who led Italy out of a major financial crisis last year, would refuse to ally with a centre-left coalition because of the suspicion it would be dominated by trade unions and leftists.
Monti, who is struggling to attract votes in the centre, said in an interview with Rome's Il Messaggero daily on Tuesday: "We have nothing in common with the left-wing coalition."
He has repeatedly urged Bersani to drop leftist ally Nichi Vendola of the small Left, Ecology and Freedom (SEL) party.
But Fassina told Reuters in an interview: "I guess that Monti, like us, wants to do something positive for this country. If we do not have a majority and Monti can provide the numbers for forming a stable government, why wouldn't he do it? What is the alternative? Another election in a couple of months?"
He added: "It would be difficult to explain to the rest of the world that the saviour is not providing support for forming a government."
Fassina said the centre-left would seek an alliance with Monti to strengthen the government and reassure markets even if it had a majority by itself.
Despite Monti's lacklustre political campaign, Fassina said the outgoing premier, "is an asset for Italy so in one way or another he should stay in the front line." Monti replaced Berlusconi in November 2011 as Italy slid towards a perilous debt crisis.
Fassina said the problems around an alliance stretching from Vendola to Monti "are enormously exaggerated," adding that Vendola had signed a pact to follow majority decisions in the coalition, in which the PD would be dominant.
"Vendola is not the extremist that people like to describe for electoral purposes," Fassina said, referring to the openly gay poet's 7-year tenure as governor of the southern region of Puglia where he has been widely described as a moderate. "There is a pretty good track record," Fassina said.
He added that he was less worried about Vendola than the danger that Monti would not get enough votes to help the centre-left form a majority because of the rise of the anti-establishment 5-Star Movement and Berlusconi's centre-right, describing them both as "populist forces"
Beppe Grillo, the 5-Star leader, has been boosted by a wave of recent corruption scandals and is now running third on close to 20 percent according to polls, well ahead of Monti.
But Fassina added: "Our feeling is that with Monti we will have a majority in the Senate large enough to have a stable government, this is what we understand from the latest polls."
He said the centre-left believed the most urgent reform in Italy was to streamline a notoriously bloated and inefficient public sector, address rampant corruption and transform a byzantine system of justice that causes years of delays in civil as well as criminal cases, a major disincentive to investment.
He said a plethora of local, central and regional authorities had caused paralysis and created hundreds of small and inefficient companies providing local services. The centre-left would close many of these companies and merge others.
Despite the feeling of many senior businessmen that reforming the labour market is the most urgent measure for a new government, Fassina said existing legislation was in line with the European average.
However, he said Monti's labour reforms had failed to close the gap between highly protected older workers and young people on precarious temporary contracts. The PD would encourage permanent contracts by cutting tax costs for companies.
Fassina said Berlusconi would try to retain enough influence to protect his personal interests through blocking anti-trust and anti corruption legislation and preventing an extension of the statute of limitations that has saved him in several fraud trials.
But if a stable government was formed after this election, Berlusconi would be marginalised and lose leadership of his People of Freedom party (PDL) within two years.
(Writing by Barry Moody; Editing by Giles Elgood)