Polls run in national dailies El País and El Mundo suggest prime minister Mariano Rajoy and his conservative Popular Party (PP) will pick up just over one in four votes on Sunday in what has been widely touted as the closest election race in the history of Spain's young democracy.
A survey carried out by pollsters Metroscopia for the centre-left El País newspaper has the PP winning 25.3 percent of the vote, while that figure is 27.2 percent in the centre-right El Mundo newspaper.
These results would see the government down more than 80 seats on the 186 seats it won in the landslide 2011 election victory. The PP is therefore set to lose the absolute majority it currently boasts.
Coming in second place, according to both El País and El Mundo is the country's other large established party - the Socialists.
The El País poll has the Socialists on 21 percent of the vote while El Mundo suggests their share will be 20.3 percent. This would see the Socialist party - widely blamed for its handling of Spain's economic crisis - with as few as 76 seats, out of a total of 350.
But in elections that are widely touted as spelling the end of a bipartisan rule in Spain, two new parties are also set to win close to 20 percent of the vote.
In something of a surprise result, the Metroscopia poll in El País has the left-wing, anti-austerity party Podemos in third place and the right of centre Ciudadanos party in fourth place.
The El Mundo poll, meanwhile, has Ciudadanos in third place and Podemos in fourth place, which is more in line with poll results over the last few weeks.
Predicted voter support for these two parties would see them winning around 60 seats each in a system where the two biggest parties are favored in many of Spain's smaller provinces.
However, with a recent poll from government research body CIS suggesting some four in ten voters are still undecided, Sunday's results could still throw up a couple of surprises.
Voter turnout is also expected to be high as Spain shift from being a two-party system, to a two-bloc system with two parties on the left of the political spectrum and two on the right.