A composite wall, ceiling or floor panel (10), system and method, including a sheet (14) having a first face (18) including at least one first mounting portion (16), and at least one formwork member (20) with at least one second mounting portion (30) arranged to engage with the first mounting portion of the sheet to retain the sheet and said at least one formwork member together. Structural support comes from piers (for a wall) or beams (ceiling or floor) formed in the spacing between adjacent formwork members. The formwork members act as the core of a wall, ceiling or floor panel. An external coating (123) is applied to the formwork members, such as spray shotcrete or render. Channels (28) formed by the formwork members defines integrated ducting for services to be run.