[en] Computing the hyperfine coupling constants and parity non-conservation (PNC) effect parameters in a few heavy atomic systems has been performed and based on the combined relativistic nuclear mean-field theory and relativistic many-body perturbation theory (PT) formalism with accounting for the interelectron correlation and dominant QED corrections. Results of estimating hyperfine structure constants and PNC parameters for different heavy atoms (caesium, ion of barium, thallium, ytterbium) are presented and compared with other theoretical and experimental data. The spin-dependent contributions to the PNC amplitude for the caesium are presented too. (paper)