Current paper deals with stiffness optimisation of silver birch (Betula pendula) plywood rib stiffened hollow core sandwich panels. Such a structural solution has several advantages over conventional plywood boards - weight and material savings are just some of them. However hollow core panels demand special attention to accurate structural design for selected loading scenarios. In order to acquire mechanical behaviour of plywood boards and rib-stiffened panels the ANSYS finite element (FE) calculation code has been employed linked with predefined design of computer experiments. Based on acquired mechanical responses from FE analysis metamodelling technique has been implemented to optimise cross-section parameters of rib stiffened panels. Optimisation results demonstrated that such a strategy allows to obtain an optimum solutions and to substitute conventional thick plywood boards (h>30mm) with equivalently stiff hollow core sandwich alternative. This could be of particular interest for applications where bending is dominating load case and structure span length is at least 20 times larger than thickness. In such a case weight reduction of plywood hollow-core panels may reach up to 45 %, comparing with conventional plywood boards. Experimental validation of obtained optimal designs confirmed the match between load/deflection curves among conventional and equivalent rib stiffened panel designs. Some slight stiffness deviations observed in tests are mainly caused by geometrical intolerances included in manufactured prototypes.