Had he lost the vote on Monday, Conte would have been forced to resign.

After his appeal to opposition and non-aligned lawmakers to back him following last week's walk-out by former premier Matteo Renzi's Italia Viva party, Conte's government won the lower-house vote by 321 to 259.

The margin was wider than expected and gave the government an absolute majority in the 629-seat chamber.

Conte will face a tougher test on Tuesday in the upper house Senate, where the government had only a slim majority even when Italia Viva was still part of the coalition.

Looking to entice centrist and liberal lawmakers, Conte promised to revamp his policy agenda and shake up his cabinet, saying he wanted to modernise Italy and speed up implementation of a recovery plan for the recession-stricken economy.

"I ask for clear, transparent support, based on the strength and clarity of the proposal," Conte told the Chamber opening the confidence debate, condemning Renzi's tiny centrist party for abandoning the 17-month-old coalition.

"Let's be frank, we can't undo what has happened, we can't regain the trust and confidence that are essential conditions for working together. Now we have to turn the page," he said, apparently closing the door on any reconciliation with Renzi.

Italia Viva said it withdrew from the cabinet because it did not agree with the prime minister's handling of the twin coronavirus and economic crises.

Without mentioning Renzi by name, Conte said there was "no plausible justification" for his walkout, which risked damaging Italy at a time when it was president of the G20 group of major global economies.

Italy's borrowing costs rose on Monday as financial markets fretted over the political crisis, but a large-scale sell-off has been averted by the European Central Bank's large-scale purchases of Italian assets.

Attention now turns to Tuesday's vote in the 321-seat Senate.

Australian Associated Press