He added that they had not reached an advanced stage by the time they were intercepted by the Ministry of Interior. He said information of the plots came from interviews with suspects, and there had not been physical attempts on his life.
"It's one of the reasons that he's not made a public appearance," the officer said. "It would be very unsafe for him."
The then General Sisi was Defence Minister when he issued an ultimatum to Morsi last year to make concessions to anti-Brotherhood protests or face the consequences.
When Morsi refused to do so, Sisi had him arrested, and declared the chief justice, Adly Mansour, interim President with the backing of the state-backed religious authorities and a number of non-Islamist politicians.
That was followed by the violent dispersal of protests, in which more than 1000 people were killed. Since then, hundreds of police officers and soldiers have been killed by militants.
Sisi, who was promoted to field marshal before he stepped down, is expected to win by a large majority.
The Brotherhood has been declared a terrorist organisation and most of its leaders are in jail, while other potential opponents have either declared a boycott or stood aside for him.
The only other candidate is Hamdeen Sabbahy, a Nasserist leftist who came third in the 2012 elections won by Morsi.