"The Congress has decided to support the JD-U government. We have handed a letter to Governor D.Y. Patil supporting the government," state Congress president Ashok Choudhary told media here.
Manjhi - from the Mushahar community - was SC/ST welfare minister in the Nitish Kumar cabinet. He is legislator from the Makhdoompur assembly constituency.
Choudhary said the Congress has four legislators in the 243-member Bihar assembly and they will support the government.
Congress legislator party leader Sadanand Singh said the party will continue to support "a secular government" in the state.
After outgoing chief minister Nitish Kumar resigned Saturday following his party's debacle in the recent Lok Sabha election, it was speculated whether the Congress will support the government.
At present, the Janata Dal (United) (JD-U) has 117 legislators and enjoys support of one CPI member and two Independents. The half-way mark in the 243-member Bihar assembly is 122.
After the JD-U snapped its 17-year alliance with the BJP last year, the Congress legislators have voted in favour of the Nitish Kumar government in the state assembly.