Investors are particularly concerned that a Syriza-led government could result in the undoing of the austerity policies implemented under Samaras' present government. The party has always said it would "tear up" the tough conditions of Greece's bailout, which were required by the troika of international creditors, the European Union, International Monetary Fund (IMF) and European Central Bank (ECB).
The Athens stock exchange fell up to 10 percent on Monday, before paring some losses, and was trading 0.3 percent lower on Tuesday. Meanwhile, Greece's borrowing costs remained above 9.5 percent.
Read MoreGreek stocks tank as snap election called
With a public debt to GDP ratio of 175.5 percent, the country has the highest debt in the euro zone, but Greece's politicians are keen to calm European lenders that Greece isn't about to default – or leave the single currency union.
Syriza's leader, Alexis Tsipras, said the onerous terms of the bailout would be "overturned" if the party got into power, but insisted the country would honor its debt obligation, Reuters reported.
"We want to show our European partners that this debt has to be restructured," Milios added. "It's not possible to create enormous primary surpluses just to pay for a debt which cannot be serviced. It's not only Greece in this situation, we have to open it as a European problem and find a solution."
Milios said Syriza's main aims were to clean up the country's "corrupt" state. He added that combating tax evasion would help create new revenues for the government and attract foreign investment.