The time relaxation of the magnetization in a FeTe0.7Se0.3 crystal has been investigated at different temperatures for applied magnetic fields up to 9 T. A power law time dependence of the magnetization has been observed in a wide range of times, temperatures and magnetic fields, being a sign that vortex motion occurs in the single vortex creep regime. A time relaxation of the magnetic field value at which the peak effect in the m(H) curves occurs has also been observed