Eurostat, the European Union statistics agency, estimates Slovakia's 'shadow' or 'grey' economy represents 15% of the country's official GDP. Other studies have suggested the figure is as high as 17%.
Illegal labour is thought to be widespread in the business sector. Many employers and employment experts point to generous unemployment benefits, a relatively high minimum wage and high employer taxes as reasons for a burgeoning shadow economy.
The same agency also puts health sector bribes at Sk12 billion ($248 million) a year, or about $46 for each Slovak resident.
The EU warned in a recently released annual report on the country that corruption was widespread in many sectors and urged the government to take more steps to combat graft and increase transparency.