The prisoners to be released include such well-known figures as General Olusegun Obasanjo, 62, Nigeria's head of state from 1976 to 1979, and Beko Ransome-Kuti, a pro-democracy activist jailed since 1995.
But Nigeria's best known political prisoner, Moshood Abiola, the billionaire businessman who apparently won 1993's annulled presidential elections, was not mentioned in the statement from David Atta, the press secretary for Nigeria's new military leader, General Abdulsalam Abubakar.
It not immediately clear when the releases would occur. General Abubakar "has ordered the release of some detainees and prisoners to facilitate the process of national reconciliation and reconstruction," Mr Atta said.
Gani Fawehinmi, an attorney and one of Nigeria's most vocal critics of military rule, praised the move as a "joyous step towards reconciliation".
"This is incredible. This is fantastic," said Mr Fawehinmi. "This gives us hope that something good will begin to happen soon."
He noted, however, that a number of prominent political figures remained behind bars. "They must go further and release all detainees and all prisoners still in the gulag."
General Abubakar came to power a little less than a week ago, following the death of General Sani Abacha, who, during his five-year dictatorship, made the country an international pariah for its human rights record.
In announcing the release of the prisoners, the new military leader urged those granted amnesty to "co-operate" with the government to create "the country of our dreams".Reuse content