Vienna - Austria's far right parties got a massive boost in Sunday's parliamentary elections because voters were frustrated with the centrist coalition parties and not because of the rightists' anti-immigration rhetoric, experts said.

Heinz Christian Strache's Freedom Party (FPOe) won 18 per cent of the votes, up seven per cent from the last elections in 2006, according to projections based on 99 per cent of counted ballots.

Joerg Haider's Alliance for the Future of Austria (BZOe) more than doubled its votes to 11 per cent, from 4 per cent in 2006.

Together, the two parties are just one per cent behind the Social Democratic Party (SPOe), the winner of Sunday's early elections.

"The main reason was that the government's dismal performance," political scientist Peter Gerlich of the Vienna University said, explaining voters' shift to the far right.

The coalition between Social Democrats and their junior partner, the conservative People's Party (OeVP), split in July after 18 months of bickering and political stalemate.

Experts also said the two parties were successful at portraying themselves as caring for lower-income voters worried about rising prices.

Although the Social Democrats pushed a package of social spending bills through parliament mere days before the elections, the Freedom Party had more credibility with social issues, Fritz Plasser of the Innsbruck University said.

"Supporting the weak helped them," Plasser said.

Strache's anti-European Union rhetoric also resonated in a country where 47 per cent of the population think Austria has not benefited from being an EU member.

But despite these factors, there is no denying that Strache's Freedom Party, and, to a lesser extent, Haider's Alliance, banked on voters' anti-immigrant and anti-Islamic sentiments.

At Strache's final election rally in one of Vienna's working class districts last Friday, the crowd cheered loudest not when he spoke about social issues, but when he complained that foreigners were now allowed to live in social housing projects.

Haider suggested during the election race that all asylum seekers should be made to wear electronic tags to monitor their movements.

Although it is clear that both right-wing parties will play a bigger role in Austrian politics, both Social Democrats and Conservatives have so far ruled out forming coalitions with Strache or Haider.

"The SPOe will be somewhat tempted," to cooperate with the Freedom Party, Gerlich said. But his colleague Plasser said that such a coalition would create a deep split among Social Democrats.

There is also a rumor about a (Social Democratic) minority government with parliamentary support from the Freedom Party, Gerlich said. (dpa)