Ryder, plundering domestic bowling attacks for Wellington after making himself unavailable for New Zealand for personal reasons, wants a new challenge after his demolition of radio host Mark Watson in a charity fight this year and Flintoff would certainly provide that.
Flintoff, who retired from cricket three years ago, recently beat American professional Richard Dawson in Manchester on points over four two-minute rounds.
Duco Events director David Higgins confirmed talks had begun with Ryder about a fight which would probably occur on the undercard of a professional match-up featuring the likes of Joseph Parker or David Tua.
Higgins said a fight between Ryder and Flintoff could coincide with England's cricket tour of New Zealand in February and March. However, the player's manager Aaron Klee said: "It would have to fit into a window that didn't have cricket on because he couldn't do both, particularly if he was playing for the Black Caps, but we haven't made that decision yet."
Another prospective opponent is Quade Cooper, the Wallabies first-five who will fight on the Sonny Bill Williams v Francois Botha undercard in February. However, Cooper's manager Khoder Nasser is unlikely to agree to a Ryder match-up.