"Justice creates the suspicion that it decides and deliberates using criteria beyond strictly legal judgements," government spokesman Dimitris Tzanakopoulos said on Tuesday, in a comment on Monday's ruling concerning a Greek postgraduate student convicted to prison as a member of the terrorist group "Conspiracy of Cells of Fire".

"It was a bad development. Yesterday's ruling will be recorded in the 'black book' of Greek justice," Tzanakopoulos said in an interview with the radio station 'Sto Kokkino'.

A Greek appeals court on Monday refused to suspend execution of a prison sentence imposed on the 29-year-old postgraduate student known as Irianna and fellow-convict on terrorist charges Periklis, finding that they should remain in prison until their case is heard on appeal. Irianna was convicted on the basis of DNA evidence that has been contested as incomplete and therefore not sufficiently conclusive as to support a conviction.

He also repeated that Greece would attempt its return to the markets when "fully prepared," and that the aim of the programme was to enable Greece to finance its debts without support from the official sector, after being excluded from the markets for seven-odd years.

Tzanakopoulos clarified that this decision would not be based on the advice of financial houses or "market experts" but an assessment of the performance of Greek bonds. "We will make the decision when we consider that we are at the best point and will take the lowest possible risk. We want to prepare the way for after the summer of 2018, we are not interested in tapping the markets for spin purposes," the spokesman added.