"People are not choosing smaller parties because they believe in their agendas," political communications expert Spiros Rizopoulos said. "I doubt if anyone has ever read an agenda of a smaller party. It's because they want to protest a decision that has been made" that led Greece into the bailouts and the ensuing austerity.
For the past six months, New Democracy and PASOK have been uneasy bedfellows in a coalition government cobbled together under technocrat Prime Minister Lucas Papademos. The former European Central Bank head was appointed after Papandreou was forced to resign following a sudden decision to put the country's second bailout to a referendum.
The coalition, which initially also included a small right-wing party, was formed with the sole mandate of securing the country's second bailout and a massive bond swap deal with private creditors that wiped nearly €107 billion ($140 billion) off the country's national debt.
With both secured in early April, elections were called.
Samaras has insisted he will not enter into a coalition with his Socialist rivals.
"It is not in the interest of the Greek people to have a power-sharing government of this kind to exist," he told supporters at his main campaign rally in Athens on Thursday night.
But the tactic is seen as an effort to drum up the maximum support before Sunday's vote, and an attempt to force new elections by refusing to cooperate with other parties is likely to anger even members of his own party who have openly supported sharing power with the Socialists.
"Whoever dares to torpedo the creation of a coalition government won't even receive his own vote in the next elections," Athens University political science professor Elias Nicolacopoulos said.
"Whatever they may say now, however much they raise the rhetoric, in 10 days maximum they are obliged to agree on forming a government. Otherwise, they will be unable to walk on the street. ... Right now, people expect — even if they vote for anti-austerity parties — responsible behavior on forming a government."
Demetris Nellas, Nicholas Paphitis and Theodora Tongas in Athens contributed to this report.