The ALICE programme has allowed to study the hottest state of matter created in the laboratory: the strongly-interacting quark–gluon plasma (sQGP). However, some fundamental questions on the sQGP and other aspects of the strong interaction will still remain open after the LHC Runs 3 and 4. To answer such questions, the ALICE detector will undergo a major upgrade resulting in higher readout rate capabilities, an improved position resolution, as well as tracking and particle identification over a larger acceptance. Among the subdetectors considered in this upgrade, known as ALICE 3, the muon identification detector (MID) is aimed at contributing to the study of charmonia and exotic hadrons produced in heavy-ion collisions. The baseline option for the MID consists of two layers of muon chamber based on plastic scintillators bars equipped with wave-length shifting fibers and silicon photomultipliers for read out. The other component of the detector consists of a cylindrical absorber with a varying thickness in order to guarantee a uniform absorption length across the pseudorapidity range. The simulations of the physics performance and the radiation load studies for the MID subsystem will be presented.