Italy’s new left-leaning, EU-friendly government has won a vote of confidence in the lower house of parliament.

Deputies voted 343-263 in favour of the coalition between the Five Star Movement (M5S) and centre-left Democratic party (PD) following a heated debate during which the prime minister, Giuseppe Conte, was repeatedly heckled by deputies from opposition parties.

Conte, who is on his second mandate as prime minister, is attempting to turn the page after the collapse of M5S’s ill-fated 14-month alliance with the far-right League.

The government faces a second vote in the upper house, the Senate, on Tuesday. If it loses in the Senate, where its margin is slimmer, it will be forced to resign.

Luigi Di Maio, M5S leader and newly appointed foreign minister, said after the vote, “Now is the time for courage,” while his PD counterpart, Nicola Zingaretti, said the confidence win marked “another step towards changing Italy”.

Earlier on Monday, Conte pledged that the coalition would be less antagonistic and more respectful than the previous one, while committing to an ambitious programme based on a “political and social pact”.

“We must recover sobriety and rigour so that our citizens can see renewed confidence in our institutions,” Conte said. “In the coming months, we cannot waste our time with disputes and clashes.”

Conte’s speech coincided with a protest outside the lower house of parliament by supporters of the League and the smaller far-right party Brothers of Italy.

Conte said there would be a more “responsible” approach to governing, while promising more investment and a better economy and to work with Brussels to reform budget and immigration laws.

“This programme is not a mere list of heterogeneous proposals that overlap each other, nor is it a mere summing up of the different positions taken by political forces that support this initiative,” Conte said. “On the contrary, it is a programme that shapes the future of Italy.”

Conte is striving to break away from an era that saw Matteo Salvini, the former interior minister and leader of the League, mostly calling the shots within the government. The new coalition came together after Salvini’s gamble in August to collapse his alliance with M5S and force snap elections backfired.

Salvini’s hardline immigration policy is expected to be revised under the new interior minister, Luciana Lamorgese, a career civil servant and specialist in migration policy. The key economy minister role went to Roberto Gualtieri, a European parliamentarian with the PD. His first major challenge will be drafting Italy’s budget for 2020. Negotiations over this year’s budget between Rome and Brussels were so fractious that Italy was threatened with severe fines.

But Salvini, whose League party is still the biggest in Italy despite losing some of its popularity in recent weeks, is refusing to renounce his push for fresh elections. He told protesters outside the lower house on Monday that they represented “the majority in the country asking for a vote”.

“Today the division between the closed palace and the Italy in the street is evident,” he said.

Salvini, who constantly campaigned during his time in office, has held several rallies across Italy over the past week and has called for a demonstration to be held in Rome in October.