(ANSA) - Rome, February 19 - Premier-designate Matteo Renzi said he was optimistic about being able to form a new government after concluding talks with Italy's political parties on Wednesday, adding that he was set to present his executive on Saturday.

The 39-year-old Democratic Party (PD) leader is poised to become Italy's youngest-ever premier after last week torpedoing the coalition government led by his PD colleague Enrico Letta for being too slow on enacting reforms to streamline the political system and revive the country's troubled economy.

"After a day and a half of very tough meetings, dialogue and analysis, I'm decidedly convinced that there are the conditions to do an excellent job," Renzi said. He said he would announce whether he has dropped his formal "reservation" about accepting a government mandate from President Giorgio Napolitano on Saturday when he will present his cabinet before the executive faces confidence votes in parliament from Monday.

The premier-designate, who has been compared to a young Tony Blair and intends to present an ambitious reform programme, said he was impressed by the parties' awareness of Italy's "dramatic situation" - with one exception.

That was a reference to the meeting with comedian-cum-politician Beppe Grillo, the leader of the anti-establishment 5-Star Movement (M5S), which Renzi cut off after just minutes when Grillo erupted into an angry barrage and would not let anyone else speak.

"I'm sorry so much for those who voted 5-Star," Renzi said after the meeting via his Twitter account, @matteorenzi.

"You deserve more, friends. But I promise you that I'll change Italy for you, too". The PD chief said his new administration would be supported by the same majority as Letta's, with Deputy Premier and Interior Minister Angelino Alfano's New Centre Right (NCD) as junior partner.

Renzi called the NCD reform programme, which also reportedly rejected a wealth tax and called for a justice minister to defend suspects' rights, "very good and positive".

The NCD, a group of centre-right moderates who split from Silvio Berlusconi's revived Forza Italia (FI) party when it rejected the ex-premier's bid to scupper Letta after the PD insisted on a Senate ban for the media magnate following a tax-fraud conviction, had warned Renzi beforehand that his government would never come to life if its demands were not met.

Three-time premier Berlusconi, meanwhile, reiterated his stance that FI would conduct "responsible opposition" to the government while cooperating with Renzi on reforms.

Renzi last month reached a deal with the centre-right leader for a new election law to replace the dysfunctional system that was declared unconstitutional in December.

Renzi also has an agreement with Berlusconi to change the Constitution to strip the Senate of its lawmaking powers to make it easier to pass legislation, turning the Upper House into a leaner assembly of local-government representatives, and to abolish the country's provincial governments and bring some powers back to central government from the regions.

"The country needs to become a governable country," said Berlusconi after the meeting.

"We wish the premier-designate and his team all the best," added the 77-year-old billionaire, who led FI's delegation despite his ban on office.

"We're also in favor of rejuvenating the government. Today I met a premier who's half my age - a good sign for the renewal of the ruling class".

While wishing Renzi well, Berlusconi has said he does not agree with the political maneuvering that is set to see him become premier and thinks the country should return to the polls. Berlusconi was the last premier to be elected by the Italian people.

The most recent of Berlusconi's three governments collapsed when he resigned in November 2011 with Italy in danger of a Greek-style financial meltdown.

It was replaced by the emergency technocrat administration of Mario Monti, which made way for outgoing Letta's coalition government after last year's inconclusive general election.

Renzi met Napolitano later on Wednesday to update him on this week's consultations and he also had talks with Bank of Italy Governor Ignazio Visco. He said he will spend Thursday in "preparation" for his incoming government's plans once in office.