Italy must quickly cut energy bills for firms and households even if it means hiking the country's towering public debt, the leader of a new centrist group competing at this month's elections told Reuters.

Polls suggest the Sept. 25 ballot will be won by a rightist alliance but Carlo Calenda, a former businessman and industry minister, said the race is far from over and he believed his centrist "Action" party could deprive it of victory.

Mario Draghi's outgoing government should invest 10 billion euros ($10 billion) to help major gas consuming industries and reimburse people part of the increases in gas and electricity costs that have already eroded their budgets, Calenda said.

The price of energy from renewable sources should also be decoupled from the price of gas, he added.

"As is always the case at a time of emergency, the quicker you act the less you have to spend," Calenda said in an interview on Thursday in his campaign headquarters in central Rome.

Across Europe governments are pushing through multibillion-euro packages to prevent utilities from collapsing and protect households from soaring energy costs triggered mainly by the fallout from Russia's invasion of Ukraine.

Draghi's government has reshaped the budget this year to set aside more than 50 billion euros for energy price relief without resorting to debt. Calenda said that would not be enough and fresh borrowing should not longer be a taboo.

Hesitation would mean greater damage to the economy, higher costs in welfare benefits and company bankruptcies, and it would also risk weakening Italian support for sanctions against Russia, he said.

He accused the rightist League party of "favouring Russia" by drawing a link between the sanctions and soaring energy prices.

"If we don't act we must be aware that public opinion will begin to waver over supporting Ukraine," he said.

Once an executive with luxury sports car maker Ferrari, Calenda formed Action in 2019 and last month he teamed up with former premier Matteo Renzi to run together at the election on a joint ticket with Renzi's Italia Viva party.

The centrist alliance is polling at between 5% and 8% but Calenda said his sights were on 12% which would be enough to deprive the conservative bloc of a majority in the Senate.

"We can take a lot of votes from the centre-right," he forecast. At that point, he said he would push for a reinstatement of a national unity coalition led by Draghi involving all the main parties.

BATTLING FOR DRAGHI

Calenda presents Draghi as Action's candidate for prime minister even though the former European Central Bank chief is not running and has given no indication he wants a second term.

In the case of a hung parliament "I believe (President Sergio) Mattarella will ask Draghi to carry on," Calenda said.

If the right, spearheaded by Giorgia Meloni's nationalist Brothers of Italy party, fails to win a clear victory at the election Calenda ruled out that Action could offer them support to muster a parliamentary majority.

He denied he would back any attempt by the right to push through constitutional change to introduce the direct election of the head of state, a reform dear to Meloni.

The Italian president is currently elected by parliament and any change would require a two-thirds majority in parliament or a popular referendum.

Calenda, 49, started his political career in 2013 with Scelta Civica, a centrist party founded by former prime minister and EU commissioner Mario Monti that lasted only a few years.

He then joined the centre-left Democratic Party (PD) before founding Action in 2019. Last year, he ran to become mayor of Rome, but came third in the ballot won by the PD's candidate.

Critics say Calenda, who comes from an upper class background, is out of touch with ordinary people, while his admirers compare him with French President Emmanuel Macron.

"Our political positioning is very similar to Macron's," Calenda said, pointing out that in the European Parliament Action is in the same centrist 'Renew Europe' group as Macron's La Republique en Marche.

He said Italy needs to overcome ideological divides to create "an area of common sense ... which has a lot to do with what Macron created in his last election campaign."

($1 = 0.9896 euros)

(Writing by Gavin Jones; Editing by Frank Jack Daniel)