By Alkman Granitsas And Stelios Bouras 

ATHENS--Fears that Greece's high-stakes parliamentary vote for a new president could herald a return to economic turmoil have stalled business development and foreign investment, business executives and investors say.

If Prime Minister Antonis Samaras and his ruling New Democracy party aren't able to win the vote in one of three tries this month, Parliament would be dissolved and national elections called. Lawmakers failed to elect a president last week in the first round of voting. A second parliamentary vote takes place this week and the last is tentatively scheduled for Dec. 29.

Many in Greece's business community fear new national elections could bring to power the antibusiness opposition Syriza party, which wants to discard the bailout package run by the European Union and the International Monetary Fund. The party is currently leading by 2-5 percentage points in public opinion polls.

The prospect of a Syriza victory sends shudders through businessmen such as Theodoris Sietis, chief operating officer of Eltex Anemos SA. "Greece's economy is at a critical juncture," he said. "At a time when investment should be happening and the country should be moving forward quickly, instead things are slowing down."

Mr. Sietis led his energy company to a listing on the Athens Stock Exchange in July, the first and only listing on the exchange since the country's debt crisis erupted five years ago.

The listing was seen by many international investors as a sign Greece was clawing its way back to normalcy after a wrenching downturn that wiped out more than a quarter of the economy and sent the stock market to its lowest point in decades.

Eltex Anemos, a unit of Greek construction giant Ellaktor, raised some EUR35 million ($42.8 million) in July. The sum was part of an ambitious EUR200-million plan to build wind parks across Greece, a sector many here see as a catalyst for future economic growth.

Now the plan is on hold. "There are a number of decisions we would have taken by now, but instead we are waiting," he said.

So is the government. Two planned privatizations due this month--one for an airport on the island of Crete, another for the national power grid--appear likely to be pushed back several weeks, officials say. Another privatization, of a government-owned tourist property that was sold off earlier this year, has been stalled awaiting final approval, a businessman familiar with the deal said. Meanwhile, tourism industry executives warn that early bookings for next year's summer tourism season--normally made in December--have also stalled.

Fears of a descent back into economic tumult sharpened last week as investors dumped Greek stocks and bonds amid the political uncertainty. The Athens Stock Exchange has lost more than EUR10 billion in value this month. As Greek bond prices fell, the yield on Greece's benchmark 10-year government bond soared to around 9%--erasing all of its gains over the past two years--before staging a modest recovery in the past few days.

Now, those fears are also seeping into the economy. After six years of recession, Greece returned to growth this year. Its gross domestic product is projected to expand 0.6% this year and 2.9% in 2015.

The prospect of a protracted period of political turmoil threatens to upend those forecasts. Greece's central-bank governor, Yannis Stournaras, warned last week that the political uncertainty was "taking on serious dimensions" and could have lasting damage on the country's nascent economic recovery.

"There is a risk that the growth, that has only just started to resume, may be halted," Mr. Stournaras said. "But there is also a large risk of irreversible damage being done to the Greek economy."

Like Mr. Sietis and others, businessman Nikos Manesiotis is worried. He runs a family-owned importing company started by his grandfather in 1919. Since its founding, the company, based in the Athens port of Piraeus, has weathered several wars, foreign occupation, banking crises and countless changes of government.

The most recent hardship was the credit squeeze at the depths of the eurozone crisis in mid-2012. With Greece's future in the eurozone in doubt, many foreign suppliers cut credit lines and demanded cash only from companies such as Mr. Manesiotis's firm. Anticipating similar adversity, Mr. Manesiotis, who imports spices, pet food and tin, has slowly started limiting the credit terms he extends to some of his own customers in Greece. "In the past few months, I have been offering some of my customers 40 to 45 days of credit, as opposed to 60 days. We need to be careful," he said.

Foreign investors are also cautious. This month, dozens of the world's top fund managers gathered in New York's Metropolitan Club for a conference touting investment deals in Greece. On offer was everything from distressed assets to real-estate investments to shipping portfolios. But there were few takers.

Instead, investors "are all staying on the fence," a government official said, recalling the mood at thegathering. That compares with a few months ago, when Greece's turnaround appeared to herald more prosperous days ahead.

"There is now a feeling of wait-and-see, and I do sense a reversal in sentiment," said a senior government official who tracks foreign investment in Greece.

"People are not leaving the room, they are still negotiating contracts," he said. "They are still paying for lawyers and engineers to look at projects. But they aren't quite ready to write a check yet, either."