The coalition of the anti-establishment Five Star Movement and centre-left Democratic Party was expected to easily win, and will then face another vote on Tuesday in the upper house.
Demonstrators from the anti-immigration League and smaller far-right Brothers of Italy party protested in front of parliament, with some performing right-arm fascist salutes while others held up banners reading “Not in my name”.
Protesters outside parliament on Monday. Photo: Filippo Monteforte/AFP
The results of the vote are not expected until late on Monday.
Prime Minister Giuseppe Conte was set to outline the new government's 29-point programme, including potential reforms to Italy's controversial immigration law, brought in by previous interior minister Matteo Salvini.
Conte is expected to usher in a “season of reforms” under a spirit of “new humanism” which hopes to row back a season of bitter fighting and anti-immigrant propaganda under the previous tie-up between the Five Star (M5S) and Salvini's League.
The programme will focus on improving the lives of the poor and disadvantaged, from income support for the lowest earners to help for the disabled and earthquake victims, as well as tackling inequalities in the workplace, the housing crisis, and the mafia.
Prime Minister Giuseppe Conte (C) preparing to address parliament on Monday. Photo: Andreas Solaro/AFP
The most pressing dossier on the table is the 2020 budget. Conte will visit Brussels on Wednesday to mend ties after the fall of Rome's anti-EU coalition, and begin negotiations with the European Commission for greater flexibility for debt-laden Italy.
The markets have so far welcomed the new left-leaning coalition. Milan's FTSE Mib was up slightly ahead of Conte's speech. On Friday rating agency Moody's left unchanged its rating on Italy's sovereign debt at 'Baa3', with a stable outlook.