(Adds forecasts, background)
BRASILIA, March 14 (Reuters) - A gauge of economic activity in Brazil in January fell for the 11th straight month, official data showed on Monday, indicating the country's recession deepened at the start of the new year.
The Brazilian central bank's IBC-Br economic activity index fell 0.61 percent in January from the prior month, the bank said. A Reuters survey of 13 analysts forecast a 0.10 percent increase in the indicator, a gauge of activity in the farming, industry and services sectors.
The IBC-Br index is seen as advance indicator for the gross domestic product figures released on a quarterly basis by the country's statistics agency, IBGE.
Brazil's GDP is expected to shrink 3.5 percent in 2016, following a 3.8-percent contraction last year, according to a weekly central bank poll on Monday.
On an annual basis, January's IBC-BR index fell 8.12 percent from January 2015, the central bank said.
The economic crisis in Latin America's largest economy has put the government of President Dilma Rousseff at risk. Hundreds of thousands of Brazilians flooded the streets to protest on Sunday, which could encourage Congress to impeach her, analysts said. (Reporting by Silvio Cascione Editing by W Simon)