Almost a fifth of fuel on the Greek market is adulterated, according to checks carried out by a state body.
The General Chemical State Laboratory, which operates under the auspices of the Finance Ministry, conducted almost 1,900 checks on fuel samples in 2010.
According to a report published on Thursday, 17 percent of these samples were found to contain adulterated fuel. The most common way of tampering fuel was to mix heating oil, which is currently taxed less, with diesel.
The state scientists found that a third of diesel samples had been adulterated.
The Finance Ministry announced plans on Tuesday to raise the tax on heating fuel, mostly in an attempt to combat this practice and tax evasion.
However, the move will raise heating fuel prices substantially as the ministry aims to tax diesel and heating oil equally.
Currently the going rate for heating oil averages at 1.046 euros per liter, according to the Development Ministry?s price observatory, while the equivalent rate for diesel stands at 1.591 euros/l.
Last October a liter of heating oil cost 90 cents, while a year ago it was around 65 cents.