LISBON (Reuters) - Portugal's ruling center-right Social Democrats have fallen behind the opposition Socialists in a popularity opinion poll for the first time since last year's election as deep austerity undermine its support.
The poll, published in the daily Correio da Manha on Thursday, showed support for the Social Democrats had fallen to 33.3 percent in September from 35.0 percent in July.
Support for the center-left Socialists rose to 35.4 percent from 30.8 percent.
Prime Minister Pedro Passos Coelho's Social Democrats, who rule in a coalition with the smaller rightist CDS-PP, have suffered a fall in support since the government announced deeply unpopular tax hikes for 2011 and 2012 to meet budget goals set under a 78-billion-euro bailout.
Support for the CDS-PP fell to 7.1 percent from 7.9 percent, the poll showed.
The survey of 600 people by Aximage pollsters took place between September 3 and 6, before the government last Friday announced new tax hikes for 2013 which have faced a barrage of criticism and are likely to undermine the government's popularity further.
The poll had a margin of error of 4 percentage points.
Criticism of the tax hikes came from unions as well as employers' organizations and grew louder this week after the country's lenders, European Union and IMF said they had agreed to ease the country's fiscal goals under the bailout.
Socialist leader Antonio Jose Seguro said after the tax hikes were announced that he would no longer support further austerity, which has pushed Portugal into its worst recession since the 1970s.
The ruling coalition has a firm majority in parliament after winning elections in June 2011, and general elections are not due for three years. But there will be regional elections in the Azores this year and a round of municipal elections in 2013.
(Reporting by Axel Bugge; editing by Jason Neely)