An apparatus for the continuous casting of metal in strip form comprising a pair of movable heat conducting metal belts, defining therebetween a mould space, means for applying coolant to the reverse faces of said belts adjacent said mould space, said apparatus including at opposite faces of said mould space a plurality of belt supports at closely spaced positions lying in a surface defining a path for the adjacent belt, and means effective independently of head of metal in the mould space for applying to each of said belts during transit through said mould space an outwardly directed force in a direction perpendicular to the path of that part of the belt to hold the same in a closely defined path in contact with said belt supports, including means for applying a subatmospheric pressure to the rear surface of at least one of said belts during its transit through said mould space, said apparatus further comprising at said casting zone a system for the application of coolant and differential pressure to the reverse face of at least one of said belts, said system comprising a rigid casing, a belt contacting surface on the outside of said casing, an opening in said casing lying within and surrounded by said surface, an inlet plenum chamber separated from said opening by a first partition, a water inlet passage to said plenum chamber, a plurality of closely spaced jet orifices formed in said first partition, the axes of said jet orifices being at a large angle to the belt in contact with said belt contacting surface, an outlet plenum chamber separated from the inlet plenum chamber by a second partition, closely arranged belt support members being arranged in said opening and supported by said first partition, said support members being level with the surrounding belt contacting surface of the casing, recessed water passages lying between said support members, the said jet orifices opening into said water passages for directing individual closely spaced jets of water onto the reverse surface of the belt in the casting zone, drain passages leading from said water passages to said outlet plenum chamber whereby the application of suction to the outlet plenum chamber draws water into said inlet plenum chamber and directs closely spaced individual water jets onto the reverse surface of the belt and simultaneously creates reduced pressure conditions in said water passages between said belt support members to draw the belt against said support members to define the path of the belt through the casting zone.