The compositional dependence of the real (ε') and imaginary (ε'') parts of complex dielectric permittivity (ε*) and loss tangent (tan d) for Mn0.7+xZn0.3SixFe2-2xO4 (x = 0.0, 0.1, 0.2 and 0.3) spinel ferrite series was investigated over wide frequency (f = 20 Hz to 1 MHz) and temperature (T = 300 K to 673 K) ranges. Frequency dependence of ε',ε'' and tan δ has been explained based on the two-layer model of dielectrics. The nonlinear relationship between ε'(f) and σ'(f) suggests multi-relaxation process and formation of a broad hump in ε'(f, T) plots indicates collective contributions from electrons and holes to the polarization. The scaling by normalized frequency (f/fc) and scaled frequency (f/σdc) are found successful for ε' in high-frequency regime only while scaling found successful for ε'' over the whole range of frequency. The suitability of various scaling parameters was also tested for the master curve generation. The co-existence of localized and delocalized relaxations is verified.