VELIKA, Greece—The talk among farmers in this small Greek village these days is about the pain inflicted by the strict terms of the European Union’s bailout of their country, as well as the potential perils of rejecting the deal and, perhaps, facing a future outside the euro zone.

How voters in Greece’s countryside weigh these factors will play a large part in determining the outcome of what is expected to be a close race in critical national elections Sunday between the conservative New Democracy party and its antiausterity, left-wing rivals, Syriza.

“I feel like we’re on a tightrope,” said Chrysostomos Stratouras, a 48-year-old who grows potatoes, wheat and olives on land tilled by his family for generations. Ordinary Greeks are under enormous economic pressure, he said, and “an empty stomach is a bad adviser.”

But Mr. Stratouras said that for him, the choice is clear. He plans to vote for New Democracy, which supports the EU’s rescue package and the tough restructuring program that goes with it, even though he thinks it is “murderous.” The alternative, he said, is simply too dangerous.

Rural voters backed New Democracy by a significant margin in national polls on May 6, helping the party finish slightly ahead of Syriza, which has pledged to annul the EU agreement and restore government spending, moves that could put Greece’s future in the euro area at risk.

Neither party won enough support on May 6 to form a government, forcing Sunday’s repeat vote. Recent public-opinion surveys indicate a dead heat between New Democracy and Syriza. Both have been trying to woo people in the villages.

“Rural areas are very important for us,” said a New Democracy official. He said the party has been making a big campaign push in the countryside in recent weeks. “We’re trying to explain our program door-to-door,” he said.

Syriza—whose core support is in Greece’s recession-hit cities, where the party won by wide margins in May—also has stepped up its efforts, said Nikos Pappas, a senior Syriza official. One focus, he said, has been rural pensioners, whose state benefits have been cut.

Village residents have been more insulated than city dwellers from the worst effects of the economic crisis that has engulfed the country. Kitchen gardens, chickens and livestock provide a cushion of food when times are tight. And most villagers own homes, so they don’t pay rent.

Still, the downturn and government austerity measures are increasingly biting in the countryside, including here in Velika, whose 300 people live between a mountain ridge and the Aegean on the southeast coast of the Peloponnesian peninsula.

“The village has become a lot poorer,” said Mr. Stratouras. He said farmers’ incomes are being squeezed by tax increases—such as a higher value-added tax that has lifted the cost of fertilizer and other inputs—and higher costs for electricity and gasoline.

Efi Hatzichristoforou, 49, and her husband, who lost his job at an olive-oil factory after the downturn started, are both unemployed. They have been eking out a living with odd jobs, such as packing potatoes harvested on local farms, since they don’t have fields of their own.

Ms. Hatzichristoforou, who lives in Velika, said she is afraid their electricity will be cut off soon, since they haven’t been able to pay the power bills. “In the situation we’re in right now, we can’t be sure who to believe, or what is wrong and what is right,” she said.

New Democracy’s message to voters is one of relative stability. The party says it won’t abrogate Greece’s loan agreement with the EU and International Monetary Fund, but that it will seek to renegotiate parts of it in an effort to stimulate growth.

“We need a stable government that can deal with the critical problems that Greece faces,” said Stathis Anastasopoulos, the New Democracy mayor of Messini, the municipality to which Velika belongs.

He said the bailout needs to be amended to include “development measures,” but said Syriza’s approach risks “isolating Greece from the international community.”

For its part, Syriza says New Democracy is overstating the risks. Alexis Tsipras, Syriza’s candidate for prime minister, argues that even if Greece scraps the loan deal, the EU wouldn’t dare to cut off financial assistance or expel the country from the common currency.

People in Velika aren’t so sure. Fears of any more instability in an already uncertain environment seem to be bolstering support for New Democracy.

“I don’t like Tsipras’s ideas,” said Mr. Stratouras’s 23-year-old son, Panagiotis. “If we leave the euro, we will go back 100 years,” he said. “Getting the euro was a big step forward. We can’t go back.”

The younger Mr. Stratouras moved back to Velika last summer from Athens, after wages at the bakery where he worked were cut to €25 a day ($31) from €45. He couldn’t afford to live in the city with that reduced salary, he said.

Now, he works at a bakery in a city near Velika and toils in his family’s fields. “I have dreams. I want to start a bakery, get married, have a family,” said Mr. Stratouras. “But now, everything is on hold. We don’t know what will happen.”