Abstract: A tray system for use in the packaging of stacked rubber bales, which is adapted to support and stiffen one or more rubber bales when carried thereby such as to control lateral movement of the rubber and to increase the compressive modulus of the stack. The system comprises a plastics base tray for providing a lower support on which bales which has depressions arranged and dimensioned such that the rubber of a bale placed on the base portion can flow into these depressions whereby part of the rubber of the bale effectively acts as a structural part of the tray to provide additional rigidity and strength to the resulting overall package. Intermediate trays are located between adjacent bales in the stack and have surface irregularities for mechanically engaging the rubber bales disposed immediately above and below that tray such as to reduce lateral cold flow of the rubber.