The government has submitted to a European ruling which branded the ban on prisoner votes a breach of human rights.
The details of the changes are yet to be announced officially. Moves being considered include only denying the vote to prisoners with longer sentences.
The fact the ruling emanates from the European Court of Human Rights is likely to raise Conservatives' hackles over Europe.
Prison reform campaigners welcomed the move to scrap the blanket ban, arguing the legislation - which dates back to 1870 - is outdated.