The ex-president in a book written by Segun Adeniyi, titled 'Against the Run of Play', said was not comfortable with how Jega handled the elections.
The election was scheduled for February 14, 2015, but Jonathan's administration shifted it by six weeks.
Jonathan said: “I was disappointed by Jega because I still cannot understand what was propelling him to act the way he did in the weeks preceding the election.”
“As at the first week in February 2015 when about 40 percent of Nigerians had not collected their PVCs, Jega said INEC was ready to conduct an election in which millions of people would be disenfranchised.”
The former president also said he had a meeting with Jega to express his reservations about the preparedness of INEC for the elections, but he insisted that it would go ahead.
Jonathan said: “Of course, the Americans were encouraging him to go ahead yet they would never do such a thing in their own country. How could we have cynically disenfranchised about a third of our registered voters for no fault of theirs and still call that a credible election?”
“The interesting thing was that the opposition also supported the idea of going on with the election that was bound to end in confusion”.
Jonathan in the book also defended his decision to postpone the election, saying it was for security reasons.
He said: “When the military and security chiefs demanded for more time to deal with the insurgency, the reasons were genuine”.
“As at February 2015, it would have been very difficult to vote in Gombe, Adamawa, Borno and Yobe states. But moment all the arms and ammunition that had been ordered finally arrived, the military was able to use them to degrade the capacity of Boko Haram to the level in which they posed the threat to the election.”