The invention refers to the production of construction materials, it can be used to produce fast-curing building blocks using locally-based fillers. A method for producing economical blocks that contain fibre from locally available fillers such as hemp and flax shives, rape, straw or other biological fibres – reeds, bamboo, wood chips and magnesia phopshate cement, which provides quick bonding and strength.The blocks are proposed to be manufactured in mobile type factories near the filler location as it occupies most of the block volume. The proposed method allows it to be also used after natural disasters in order to ensure the rapid availability of building materials by producing them on the spot with small quantities of materials delivered.The proposed method differs from other with the filler – organic fibres, which allow magnesium phosphate cement block to provide both strength and satisfactory thermal insulation. As well as the method used in forming the material in blocks distinguishes it from traditional magnesium phosphate cement application methods.