The tax will be applied to all imported fossil fuels, amounting to around 0.3 Swiss francs (about 0.25 U.S. dollars) on each liter of heating oil and 0.25 Swiss francs (about 0.2 U.S. dollars) on a cubic meter of gas, the official Swissinfo websited reported.

According to a deal agreed by the cabinet and parliament earlier this year, the CO2 tax becomes mandatory in 2008 since Switzerland failed to reach its own emissions reduction target for 2006.

It had pledged to cut last year's emissions by at least 6 percent compared with 1990 levels, but only managed 4.5 percent.

The Federal Environment Office said emissions did go down between 2005 and 2006 but the mild winter in Switzerland should have led to a greater reduction.

The 6 percent cut was seen as necessary for Switzerland to meet its commitments under the Kyoto Protocol, which calls for an 8 percent reduction by 2012 in order to combat climate change.

The tax will be increased in stages in 2009 and 2010 if emission levels do not come down to satisfactory levels, Swissinfo said.

The government said the new levy was an incentive more than a tax, since it would encourage industry and the public to use fossil fuels more efficiently and trigger investment in renewable energies.