France's lower house of parliament approved a hotly debated overhaul of the country's byzantine pensions system early Wednesday, clearing a major hurdle for one of President Emmanuel Macron's signature reforms.

The law passed shortly after midnight after two no-confidence votes introduced by the opposition failed against Macron's centrist majority.

The attempt to topple the government came after it employed a rare constitutional measure to cut short a debate that had become bogged down in a morass of opposition amendments, effectively forcing through the bill.

Trade unions and opposition parties slammed the move as anti-democratic but their calls for fresh protests against a bill that triggered the longest French transport strike in decades fell largely on deaf ears.

Critics say the introduction of a single, points-based system will force people to work well beyond the official retirement age of 62, or face lower pensions.

The government argues that abolishing the country's 42 separate pension regimes, which offer early retirement and other benefits mainly to public-sector workers, will be fairer and end years of deficits.

Prime Minister Edouard Philippe hailed the text as a victory for "social justice", saying that "those who defend the status quo... too often are just talking nonsense."

The text now goes to the Senate, where it is also expected to face opposition, before returning to the National Assembly for final approval.

Questions remain

If passed, the reform will be phased in gradually over the coming years for people born since 1975 but will not affect the pensions of those already nearing  retirement age.

Macron's overhaul is the most extensive in a series of pension reforms enacted by governments on both the left and right in recent years, aiming to end chronic budget shortfalls as people live longer.

A government commission estimated last year that the deficit could reach as much as 17 billion euros ($19 billion) by 2025 if no changes are made.

Yet many details of the reform, including how much a point will be worth when people retire, have yet to be determined.

Many people remain sceptical of the new system, with 56 percent of voters in an Ifop poll published on February 13 saying they opposed a points-based system.

The government has promised to negotiate with unions on how to finance the new system, but it has already warned that if no deal is reached people will have to work beyond 62, one of the lowest retirement ages in the EU.