The present invention relates to a method for production of bags for the transport and storage of bulk goods or liquids, wherein use is made of tubular fabric cut into several pieces, which are then assembled together, including the steps of: providing a tubular fabric; flattening the tubular fabric to form a first double-thickness fabric having two opposite sides, respectively an internal side and an external side, extending between two flattened edges; folding-in or pleating at least one of the flattened edges of the double-thickness fabric to form a gusset; cutting the tubular fabric into pieces and assembling the pieces to form a bag; wherein the assembly of two of the pieces includes the steps of: assembling the first and second pieces by means of seams formed around or near first to fourth gusset ends.