He was 82.
Elected five times to the assembly from Wangoi in Imphal West district, Singh was a state minister (1977-79) and later became the assembly speaker in 1995.
Singh was chief minister from 1997 to 2001 of the United Front government led by his party, Manipur State Congress Party.
After completing his masters' degree (education) and teaching at the prestigious Johnstone Higher Secondary School here, Singh had joined active politics as a member of Indian National Congress in 1971.
The cremation would take place at his native village Wangoi, 35 km from here, this evening, the sources said.