"As most of the austerity measures will not be effective before next year, the government is almost certain to miss its deficit target of 3.5% of GDP for this year," the consultancy said in its winter report, adding it expected Slovenia's deficit to reach 5.2% this year and 4.7% of GDP in 2013.

"As a result, public debt should peak at 60% of GDP in 2015 before it starts to fall gradually as economic activity finally gains momentum," Ernst & Young added.

With the Eurozone mired in recession, economic activity has weakened further as demand for Slovenian exports is faltering. In addition, domestic demand is not expected to support growth, as historically low levels of confidence among consumers and businesses, and pressures from investors for more austerity measures will depress consumption and investment, the consultancy said.