Described herein are formwork modules (3) that can be used to form a staircase (4), components of the formwork module(3), and a staircase formed with such modules (3). A pre-fabricated module (3) for forming a staircase (4) is described. The has a plurality of steps (4A) with treads (4C) and risers (4B) therebetween. The module (3) includes transversely extending riser members (16) for forming the risers (4B) of a plurality of steps(4A) and a floor (8) including a plurality of floor portions (8A), each forming the floor of a respective step(4A). Side portions (10) span between a riser member (16) and floor portion (8 A) along each side of the riser member(16). The riser members(16), floor portions (8A) and side portions (10) together defining a plurality of voids (15) to receive and form settable material (12) to define the treads of a plurality of steps (4A).