Self-consistent charge extended Huckel (SCCEH) and MSX_alpha calculations performed for several metal-ligand distances have been carried out in order to investigate the superhyperfine (SHF) tensor of 'compressed' and 'elongated' NiF₆^5- complexes in LiF. The SCCEH (made for clusters involving up to 81 ions) and the MSX_alpha calculations (made for the NiLi₁₂F₁₄^- cluster) both support the idea that the VII centre in LiF:Ni⁺ can hardly be assigned to a pure Jahn-Teller centre (without any close defect) with compressed geometry, while the experimental SHF tensor of elongated NiF₆^5- species is reasonably accounted for. Also both types of calculation indicate that for the compressed NiF₆^5- complexes f_sigma(AX) can increase upon increasing the distance between Ni⁺ and axial ligands.