The measures are part an austerity programme announced in June, which is meant to reduce the budget deficit by €80bn by 2014.

Passengers boarding flights in Germany will be charged €8 for each domestic flight, €25 for medium-haul and €45 for long-haul flights. Transfer services and cargo flights are not affected.

It remains unclear whether the tax will be phased out when aviation joins the emissions trading scheme (EU ETS) in 2012, as previously announced. Combined revenues from the levy and CO2 trading are expected to amount to €1bn annually. The impact of the tax will be reviewed by mid-2012.

On Monday, a study by Michael Kloepfer of Berlin's Humboldt University concluded that the duty could breach both the German constitution and European law. The study was commissioned by the state of Rhineland-Palatinate, home to an airport used by low-cost carriers that would be heavily affected by the tax.

The government also reduced tax breaks for manufacturing industries and farmers from an eco-tax on fuel and energy. This measure is expected to generate revenues of €1bn in 2010 and €1.5bn annually in 2011-14. After protests from industry, the tax increase was lowered compared with earlier drafts.

The bill must be approved by the Bundestag, where the government holds a safe majority. The upper house of parliament, the Bundesrat, has the power to delay the bill but not block it indefinitely.

*Meanwhile, a government-commissioned report into the country's future energy policy published on Monday has sparked further reactions from the opposition and environmentalists. Green MPs claim it makes “dubious” nuclear-friendly assumptions. They will call for a special parliamentary session to clarify how the report’s authors have reached their conclusions.