Greek economy is forecast to shrink by 5 percent in 2013, according to the results of a survey by a local think tank presented in Athens on Tuesday.

A day after Eurogroup cleared a new bailout loan tranche for debt-ridden Greece, experts of the Greek Foundation for Economic and Industrial Research (IOBE) backed up suggestions by foreign auditors for the necessity of full and fast implementation of structural changes to boost growth in the country.

The figure is higher than the 4.2-percent forecast by European Union and IMF creditors who have kept Greece afloat with bailout aid since 2010.

After three years of tough austerity, amidst delays in reforms and a deteriorating economic environment internationally, Greece is still gripped by deep recession, IOBE experts noted in a latest quarterly report.

In 2012, Greece's economy shrank by some 6.4 percent, higher than earlier estimates.

Due to prolonged recession, IOBE economists expect that the country's unemployment rates, which have hit record highs in the past two years, will remain high at about 27-28 percent in 2013, in particular after the planned wave of mass sackings in the public sector in coming weeks under the latest agreement with lenders.

The firings of approximately 4,000 civil servants this year and the placement of additional 12,500 on a mobility scheme with the prospect of dismissal in a year were deemed necessary to reduce the size of the public sector and save costs.

Greece has won praises for the progress of fiscal consolidation so far, but still lags on structural changes which are considered vital to kick start development.