Athens will patiently wait until its creditors become realistic, Greece's premier said on Monday, a day after last-ditch talks between the two sides collapsed and raised fears that Athens would default and exit the eurozone.

"We will wait patiently until the institutions become more realistic," Prime Minister Alexis Tsipras wrote in the "Ephimarida ton Syndakton" daily, adding that "political opportunism" was driving the creditors to keep pressing Athens to make cuts to pensions.