The recordings include “heartfelt anecdotes” from John Lennon and McCartney about their families, as well as “playful banter”.
Omega said that while the interview provided the basis of a feature that appeared in Playboy in February 1965, the full tapes had never been published.
The recording begins with a spoken introduction by Shepherd while the band play songs including Can’t Buy Me Love and I Wanna Be Your Man.
Shepherd then carries out an in-depth interview at a Torquay hotel where the band stayed after the concert.
Omega auction manager Dan Muscatelli-Hampson said: “Unearthing gems like these is always exciting and why we love what we do.”