Glass-fibre reinforced plastic tank, for example for liquid petroleum gas under high pressure, compressed air for air brakes or for storage of acetylene. The tank is composed of two halves, the open ends of which are conically bevelled to form a male end and a female end, which are joined to each other by an adhesive. The reinforcement in the outer and inner layers of the halves contains essentially longitudinal glass-fibre strands and the intermediate layer contains essentially longitudinal glass-fibre strands and the intermediate layer contains essentially transverse glass-fibre strands. In the half with the male end, the longitudinal glass-fibre strands in the inner layer are densely located adjacent to each other, while the longitudinal glass-fibre strands in the outer layer lie in separate groups of densely arranged glass-fibre strands with the predetermined spacing between the groups to form channel-shaped spaces. In the half with the female end, the order is reverse. In order to store acetylene, a pre-fabricated absorbent body of porous material is enclosed in the tank when the tank halves are glued together.