A scion of the Nayagarh royal family, Singh represented the Kandhamal constituency in the Lok Sabha. He is survived by his wife, one son and one daughter.
He was admitted to the AMRI hospital here early this week and was on ventilator support after he complained of chest pain and difficulty in breathing. His condition deteriorated and he died around 1 a.m., a family member told IANS.
The last rites will be performed later in the day in Nayagarh, his home town, the member said.
Singh resigned from the Congress a couple of months before the general election 2014 and contested the Kandhamal Lok Sabha seat on a BJD ticket which he won with a comfortable margin.
Chief Minister Naveen Patnaik, Governor S.C Jamir, Union Tribal Affairs Minister Jual Oram expressed their deep condolences and said Singh's demise was an irreparable loss for the state.