The 21-year-old has caught the attention of several German clubs, with Schalke, Bayer Leverkusen, Borussia Monchengladbach and Werder Bremen also reportedly keen on the defender.
Mainz sporting director Christian Heidel revealed that the club have not received any official bids for the player, however, Kirchhoff himself has admitted that he is aware of interest from certain clubs.
"Interested parties have contacted my agent, that's true. For me, what matters the most is only Mainz who are my priority," Kirchhoff is reported as saying by Bild.
The German's current deal is due to expire in 2013 and although there is no exit clause in his contract, Mainz are believed to be resigned to losing the player who would cost between €5-6 million.
Kirchhoff made his debut for the club in 2008 and has so far made 24 appearances in all competitions this season.