"Democracy has not progressed in Nigeria. Corruption has not diminished," he told the BBC of President Olusegun Obasanjo's time in office.
Achebe's best-selling book, "Things Fall Apart," has sold 11 million copies worldwide.
Ibrahim Biyu of the Nigerian electoral commission told the BBC that the U.S.-based author wasn't aware of recent electoral reforms in Nigeria.
"With what we have done all is now set to conduct the election peacefully," he told the BBC. "He (Achebe) is living over there in the United States. He doesn't know what's going on in Nigeria."
But the Human Rights Watch said the government hasn't done enough to curb election-related violence.
"The arming and mobilizing of gangs by politicians to harass opponents and intimidate the voting public has already happened and there seem to be no effort to address that," Human Rights Watch's Georgette Gagnon told the BBC.
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