He was suffering from a respiratory problem for a long time. His funeral prayer would be offered after Friday prayers in Karachi, a Private news channel reported.
Khan was founding personality of the Pakistan People's Party (PPP). In 1971, he was appointed Minister for Manpower and later quit PPP after developing differences with the party.
In 1998, he joined Pakistan Tehreek-e-Insaf (PTI), but resigned from the party in 2003, citing differences with Imran Khan.
He then joined Mazdoor Kisan Party, which later merged with the Communist Party of Pakistan to form the Communist Mazdoor Kissan Party.