Greece's socialist leader Evangelos Venizelos is accusing the head of the IMF of trying to "humiliate" the Greek people.
His comments come after Christine Lagarde told the Guardian newspaper that Greeks must help themselves by paying all their taxes, and that she was more concerned about people in Sub-Saharan Africa.
Meanwhile, the Greek press are publishing a leaked memo in which a former Prime Minister warned the country may run out of money if bailout funds are cut off after next month's election.