  The noncentrosymmetric NbReSi superconductor with $T_{c} \simeq 6.5$ K is
characterized by the relatively large upper critical magnetic field. Its
multigap features were observed experimentally. Recent studies suggested
realization of P$\bar{6}$2m or Ima2 symmetry. We discuss the dynamical
properties of both symmetries (e.g., phonon spectra). In this paper, using the
ab initio techniques, we clarify this ambiguity, and conclude that the Ima2
symmetry is unstable, and P$\bar{6}$2m should be realized. The P$\bar{6}$2m
symmetry is also stable in the presence of external hydrostatic pressure. We
show that NbReSi with the P$\bar{6}$2m symmetry should host phonon surface
states for (100) and (110) surfaces. Additionally, we discuss the main
electronic properties of the system with the stable symmetry.
