Madrid, Spain (CNN) -- The campaign for Spain's parliamentary elections was concluding late Friday under the shadow of financial markets that have hammered debt-ridden Spain in the run up to Sunday's vote.
The opposition conservative leader, Mariano Rajoy, of the Popular Party, remained far ahead in opinion polls throughout the campaign and is widely expected to be elected as the next prime minister.
In a sale of 10-year government bonds on Thursday, Spain was forced to offer investors nearly 7 percent in interest, a level that eventually led to bailouts for Greece, Portugal and Ireland, and is perceived as a tipping point for a potential financial bailout.
In the closing days of the campaign, Rajoy has spoken repeatedly about the nation's deep economic crisis, which includes the sobering figures of 21.5 percent unemployment overall, a 45 percent rate of unemployment for young people, nearly five million working-age Spaniards without a job, a steep public deficit and only tepid economic growth. Some immigrant workers are also leaving the country.
Rajoy, 56, insists his conservatives can get Spain back on the right footing.
"And that is the path we are going to follow in the next four years. Austerity, respect for the taxpayers' money, not spend more than we have, not live above our means, and encourage entrepeneurs," Rajoy told a campaign rally this week.
Rajoy has said he would not cut pensions --- which the incumbent Socialist government earlier froze, to much criticism -- but he says all other issues are on the table regarding possible cutbacks to reduce the deficit.
Rajoy also promises to consider tax cuts for businesses to encourage them to hire more workers.
A Cabinet minister between 1996 and 2004 under conservative Prime Minister Jose Maria Aznar, Rajoy twice lost to Socialist Party leader Jose Luis Rodriguez Zapatero, in 2004 and 2008.
But his conservative party swept to victory in regional and local elections last May, presaging what polls predict will be a prime ministerial triumph the third time around.
Zapatero has called the early election and announced he would not seek a third term.
Rajoy's chief challenger is Socialist candidate Alfredo Perez Rubalcaba. The 60-year-old served under Socialist Prime Minister Felipe Gonzalez and most recently under Zapatero, rising to the positions of deputy prime minister and interior minister.
Rubalcaba has called on the European Central Bank to defend the euro, which Spain and 16 other nations including Germany, France and Italy use as their currency. He has said the economic crisis in Spain is bigger than just Spain itself.
"I want to insist, once again, that the solution is for the European Central Bank to take action, and to act clearly and decisively. As long as it doesn't, we are going to have this situation of uncertainty."
Spain's parliament has 350 seats, and many polls predict Rajoy will win a majority, which would give him a free hand to set policy. By contrast, if he wins the election but falls short of a majority, he would need to make deals with other parties.
That might mean joining forces with the Socialists, or numerous smaller parties -- including nationalist parties from the northern Basque region and the northeastern region of Catalonia - which typically also win seats in the chamber.
The economic protests across Spain during the past six months have been fueled by the young -- the so called 'indignants' -- but it's not clear how much impact the protesters will have on the results Sunday.
Esteban Guerrero, who's in his last year of journalism studies at university and has been active in the protests, said: "I think it's necessary to vote but that's not enough. People feel the elections won't change the situation. They won't stop the cutbacks."
Guerrero, 25, sees his own prospects to get a job after college as bleak. "I think there's a pent-up rage. The workers and young people of this country are fed up," Guerrero said. "It's been years of frustration, over cutbacks and lower salaries."
The polls in Spain are open Sunday from 9am to 8pm (3am ET to 2pm ET) and complete results are expected later that evening.