The motivation of this described research is to provide a comparative analysis of dielectric properties of two different phyllosilicates intercalated into the polyolefine based composites. For this investigation, halloysite nanotubes and montmorillonite modified with quaternary ammonium salt have been used as a nanofiller. Developed composites may find application as an insulation materials of power cables. Therefore, the proper investigation of the dielectric influences is crucial. In the first part of the paper, the structural description of used composites with different loading level of nanofiller (1, 3 and 7 wt%) and pure polymer matrix are provided. The major section of this paper is dedicated to the dielectric properties of composites in the DC and AC field. Results of measurement under DC field are described primarily by values of volume resistivity and polarization indexes. Results of DC analysis were in most of parameters conclusive, because of the changes in one order of magnitude. Nevertheless, polarization and depolarization current characteristics showed a certain improvement in terms of charging/discharging rate, which can indicate an entrapping of electric charge behavior of both nanofillers. Evaluation of composites behaviour in AC field is based on temperature and frequency dependences of dielectric constant and loss factor. These dependences are obtained by Broadband dielectric spectroscopy. Results show that halloysite nanotubes exhibits different dielectric polarization phenomena compared to montmorillonite. In particular, dielectric losses of composites with halloysite nanotubes are lower at high and expected working temperatures than dielectric losses of compound with montmorillonite. Incorporation of halloysite nanotubes into composites causes more significant relaxation polarizations. The experiment confirmed the influence of different chemical structures and incorporation of water molecules in nanofillers on the dielectric properties.