Portsmouth have released Ricardo Rocha, Benjani and Jamie Ashdown following their relegation to npower League One.
Defender Rocha, striker Benjani and goalkeeper Ashdown are all out of contract at Fratton Park and will not be offered new deals by the cash-strapped club.
Manager Michael Appleton told Pompey's website: "We've come to a point at the football club where we need to make drastic changes, with an overhaul of the playing staff.
"The finances mean I have to bring in players on lower wages than the ones who are leaving.
"Unfortunately the demands of the Championship were too much for Benjani at this stage of his career.
"Ricardo played the majority of games for me and is a great lad, like Jamie, who did ever so well when he came into the side in place of Stephen Henderson.
"Jamie is very experienced and I would be surprised if he does not find himself a Championship club, but I am looking to bring in two young keepers who will fight hammer and tongs to get into the side."