Singh, 60, a former Bihar minister, was attending a function of Nonia caste Mahasangh when he fainted on the dais. He was rushed to Patna Medical College and Hospital (PMCH) where he died, RJD sources said.
State Minister for Food Shyam Rajak, who was present on the stage when the unfortunate incident occurred, said that Singh fainted all of a sudden and was rushed to PMCH in a private car since no ambulance was available at the venue.
Superintendent of PMCH S N Sinha said Singh was rushed to the cardiology department where he died.
Singh, who hailed from Nokha is Rohtas district, was a minister in Lalu Prasad government in 1997.
Prasad himself was present at the programme.