Brazil's primary surplus surged to 128.71 billion reais ($73.36 billion) last year from 101.6 billion reais in 2010, or the equivalent of 3.11 percent of gross domestic product, according to the central bank. The government aimed to secure a 3.1 percent primary surplus - a key gauge of the country's ability to repay its debt.
A double-digit increase in federal revenues last year and a slowdown in spending by the government of President Dilma Rousseff helped the country improve its fiscal accounts and hit its budget goal.
However, Rousseff's plans to prioritize growth of at least 4 percent after a lackluster economic performance in 2011 have many worried the government is likely to boost spending as revenue growth wanes.
"In our view, the December data means a turn in the fiscal policy stance - especially towards expenditures," Itau Unibanco analysts wrote in a note to clients. "We maintain our call for a lower primary surplus this year."
Brazil posted an overall budget deficit of 107.96 billion reais in 2011, compared with a deficit of 93.67 billion reais for 2010. The overall budget deficit includes the cost of paying interest on debt.
The primary budget surplus represents the excess of revenues over expenditures before interest payments are taken into account.