Opinion polls show a hung parliament as the most likely outcome of the snap general election, with the centre-left Socialists the favourites to win the most votes but a combined bloc of right-wing parties expected to win more seats in parliament.

Third-placed in polls after the centre-right Social Democratic Party (PSD), populist, anti-establishment Chega is seen as the most likely to be able break a deadlock, but it wants to influence policies in areas such as justice, internal affairs, and agriculture in return for enabling a PSD-led government.

"We need to be part of the government to change people's lives. There will be no parliamentary agreement (to support the PSD) without a government agreement," he said.

He added that there was a "very low" chance of such a government taking over "without members of Chega" in it.

Chega's demands will be difficult to swallow, adding to political uncertainly, as PSD leader Luis Montenegro has previously ruled out any agreement with Chega.

But Ventura draws inspiration from Italy, where centrist parties backed a coalition led by the hard-right Brothers of Italy.

Chega supports the death penalty, chemical castration for repeat rapists and wants zero tolerance for illegal immigration.

It has said it wants Portugal to have more freedom from the European Union to pursue some bilateral economic ties and defends a new EU treaty on immigration.

Chega has grown rapidly since its creation in 2019, when it won 1.3% of the vote in an election that year and the far-right's first seat since the end of Portugal's dictatorship in 1974.

In a January 2022 election, Chega got 7.2%, and opinion polls point to it winning more than 15% in the upcoming ballot.

Far-left parties accused Chega of fascism, xenophobia and racism but Ventura rejected those labels and said his party "touches on issues that interest people", such immigration and corruption.

Socialist Prime Minister Antonio Costa resigned on Nov. 7 over an investigation into alleged illegalities in his government's handling of several large investment projects. Costa has denied wrongdoing and remains head of a caretaker government.

(Reporting by Sergio Goncalves and Miguel Pereira; editing by Charlie Devereux and Alex Richardson)

By Sergio Goncalves and Miguel Pereira