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.
