•Natural fibre inclusion in soil blocks positively affects mechanical properties.•Fibre reinforced soil blocks have improved resistance against wearing and erosion.•0.5% fibre content by weight is recommended to practitioners for use.•Correlations between properties do not follow those for binder stabilised blocks.•The importance of soil type vs. fibre type depends on the property of interest. This study investigates the properties of soil blocks stabilised with fibres from agricultural waste. Laboratory experiments including density, water absorption, shrinkage, compressive strength, tensile strength, wearing and erosion were conducted on soil blocks made with two soil types and enhanced with three fibre types at 0.25–1wt.%. It was found that the physical, mechanical and durability properties of the blocks were generally improved and a recommendation of 0.5wt.% fibre content and high clayey soil are made. Many assumptions about relationships between properties established for binder stabilised blocks are found to be inappropriate for fibre reinforced blocks.