The bank's latest projections suggest that an upcoming 20 percent cut in electricity prices should shave a full percentage point off consumer inflation by the end of 2013, the source said, speaking on condition of anonymity.

The bank's estimate of the electricity cuts' disinflationary effect is about double that of many private analysts.

The more dovish forecast could make it easier for Rousseff to enact tax cuts and other stimulus measures without worrying about inflation breaching the bank's target range this year.

Independent economists on average see the IPCA inflation index finishing 2013 at 5.65 percent.

The central bank declined comment.

The bank also anticipates that an imminent rise in gasoline prices will push the IPCA consumer price index about 0.3 of a percentage point higher in 2013, the source said.

That forecast is based on Rousseff's government authorizing a roughly 7 percent increase in gasoline prices, although no final decision on the actual amount is expected until at least the beginning of February, the source said.

The central bank has declined to publicly release its forecast for the effect higher gasoline prices could have on inflation, because Rousseff has not made a decision yet.