In this article we investigate the physics and develop a theoretical model to perform computations of the Rosseland and Planck mean and multi-group opacities of weakly non-ideal Flibe plasma generated in the inertial fusion energy chamber. Ionization equilibrium and partition functions of all Flibe plasma species are modelled considering the plasma environmental influence (non-ideal effects) on the electronic structure in a static way within the chemical picture. A recently developed reduced formulation and efficient algorithm is used to solve the resulting set of equations and to determine the detailed plasma composition and partition functions for non-ideal Flibe plasma systems. The algorithm considerably reduces the computational efforts required to determine the plasma composition and allows, with considerable simplicity, the determination of all population densities of all plasma species (neutrals, ionized and excited) up to maximum ionization states equal to the atomic numbers of the involved chemical elements and considers an extensive database of energy levels of the excited states and line spectra. The calculated detailed composition is used along with the above mentioned theoretical opacity model to calculate the radiative properties of the Flibe plasma. Optical characteristics such as multi-frequency absorption coefficient, Planck's and Rosseland's mean and muli-group opacities of weakly non-ideal Flibe plasmas are calculated over a wide range of the density-temperature phase space and are presented as a set of isochors.