Promising structural reforms and spending cuts, former premier Janez Jansa of the centre-right Slovenian Democratic Party (SDS) is seen replacing centre-left Prime Minister Borut Pahor, although the last survey ahead of the vote showed his lead narrowing.
The opinion poll conducted by Ninamedia gave the SDS 28.5 per cent, with Positive Slovenia, a new centre-left party founded by Ljubljana's popular millionaire mayor Zoran Jankovic, on 24.6 per cent.
Pahor's Social Democrats were seen crashing to third place with only 14.3 per cent support.
The debt crisis in the 17-nation eurozone has already led to a change in government in a string of countries, including Portugal, Greece, Italy and most recently in Spain.
Although still in a far better state than many euro members, since joining in 2007 Slovenia's national debt as a proportion of output has roughly doubled to 45.5 per cent, according to the European Commission.
The three main credit agencies have cut their ratings on Slovenian debt in recent months, and last month interest rates hit seven per cent -- a level that forced other countries to seek outside support.
Slovenian President Danilo Turk said he hoped the candidate for forming a new government that will stabilise Slovenia's economy would be known by the end of the month.
"I believe this process (early elections) will provide a stable government that will then quickly start dealing with all the tasks ahead of us, in particular the financial stabilisation and setting the basis for economic development," Turk said after casting his vote in central Ljubljana.
Pahor's government lost a confidence vote in September after major reforms to the creaking pension system were rejected in a referendum, prompting early elections after just two years in office.
"In the first 100 days we will take the necessary measures to cut the spiral of pessimism, the lack of ambition and the drought of financial resources," the centre-right SDS manifesto promises.
If he wins enough votes Jansa will have a free hand to "act very quickly," Corinne Deloy of the Centre for International Studies and Research (CERI) in Paris told AFP.
But she added: "His grace period will be very short."
Jansa, 53, is set to assume power under dramatically different circumstances from his first term from 2004 to 2008 when Slovenia enjoyed stellar growth, unemployment under seven per cent and solid public finances.
The global financial crisis savaged the export-oriented economy -- output slumped by 8.1 per cent in 2009 -- and the government has been paying for it ever since.
Growth figures published Wednesday showed Slovenia perilously close to recession, with output shrinking 0.2 per cent in the third quarter after stagnating in the second and contracting 0.1 per cent in the first.
Unemployment hit 11.5 per cent in September, and the central bank has warned it may have to cut its growth forecast for 2012 again from the current projection of 1.3 per cent.
The outgoing government forecast a budget deficit of 5.5 per cent of output this year.
Polls opened at 0600 GMT with 1.7 million people eligible to vote. Voting was due to end at 1800 GMT, with exit polls expected soon afterwards, followed later by the first partial official results.
Voter turnout was meanwhile forecast at as high as 70 per cent.