By Jeferson Ribeiro and Alonso Soto
BRASILIA (Reuters) - Roughly nine out of 10 Brazilians disapprove of President Dilma Rousseff's austerity drive aimed at winning back investor confidence in the economy, a nationwide poll showed on Wednesday.
Brazil's sharp economic downturn is the main reason that Rousseff's popularity has fallen to the lowest level of any Brazilian president in at least the last 20 years, according to the Ibope opinion poll commissioned by the National Industry Confederation, or CNI.
The number of Brazilians considering her government "great" or "good" fell to just 12 percent, down from 40 percent in the previous Ibope poll in December. Sixty-four percent of respondents rate the administration as "bad" or "terrible, the poll showed.
Surveys by other pollsters have shown a similar trend.
Since she won re-election in October, Rousseff has made a dramatic policy shift, cutting expenditures and raising taxes on everything from fuel to imports to plug a massive fiscal gap caused by years of unchecked spending.
Ninety percent of Brazilians disapprove of Rousseff's handling of taxes while 89 reject the rise in interest rates. In its previous poll in December, Ibope said the disapproval of the government's tax and interest rate policies was 72 and 68 percent respectively.
Growing popular and political resistance to the austerity has raised fears among investors that Rousseff could at some point ease the belt-tightening needed to prevent Brazil from losing its investment grade rating.
Rousseff said in an interview with Bloomberg News on Tuesday that she will do whatever it takes to meet this year's fiscal savings goal.
Rousseff's popularity has also suffered because of a multi-billion dollar corruption scheme at state-run oil company Petrobras, which prosecutors say involves members of her own Workers Party.
CNI's head of polling, Renato da Fonseca, said however, that the economy was foremost on most people's minds.
"The economy is what is clearly influencing our poll... and the outlook is not good," Da Fonseca said.
The poll shows Rousseff's popularity fell sharply among young and less educated Brazilians, two groups that have helped keep the Workers' Party in power for the last 12 years.
The survey of 2,002 people was conducted between March 21 and March 25 and has a margin of error of plus or minus 2 percentage points.
(Writing by Alonso Soto; Editing by Brian Winter and Grant McCool)