Magnetic properties of single crystals of Mn _1–x Fe _x Si solid solutions with x < 0.2 are investigated by pulsed field technique in magnetic fields up to 50 T. It is shown that magnetization of Mn _1–x Fe _x Si in the paramagnetic phase follows power law with the exponents M(B) ~ B ^α , which starts above characteristic fields B _c ~ 1.5-7 T depending on the sample composition and lasts up to highest used magnetic field. Analysis of magnetization data including SQUID measurements in magnetic fields below 5 T suggests that this anomalous behavior may be likely attributed to the formation of a field-induced Griffiths phase in the presence of spin-polaron effects.