I've heard some sources state that the Greek government is currently running a surplus, largely due to massive cutbacks imposed by the EU banks as bailout conditions. So you have to ask why they need to make more massive savings or push large amounts of administrative effort into raising income, as oppose to helping all the Greek people who have been made destitute by austerity, given they will eventually pay back their loans with that ongoing surplus.
In fact all the Greek government have to do is change their tax laws so that people avoiding taxes are actually only evading taxes, which of course as we all know is a perfectly legal and normal practice used by anyone who matters.
What's that you say? Changing laws for political convenience would be a morally repugnant act and any government that does so forgoes any credibility? well, now you come to mention it...