A container sealing apparatus 10 comprises an electrically conductive linearly displaceable cutting member 14 operable to cut a portion 18 of sealing material from a web 16 and an independently linearly displaceable transfer member 42 comprising an electrically insulating material and extendible relative to the cutting member 14 to transfer the cut portion 18 of sealing material to an open top of a container 12 to be sealed. An induction coil 52 produces an induction field 54 for heating the cut portion 18 of sealing material, either directly or indirectly, by induction heating to seal the cut portion 18 of sealing material to the open top of the container 12. The linearly displaceable transfer member 42 holds the cut portion 18 of sealing material against the open top of the container 12 during induction heating. A field concentrator 56 is provided to concentrate the induction field 54 in a desired region away from the linearly displaceable electrically conductive cutting member 14 and other electrically conductive component parts of the apparatus 10 to optimize the induction heating of the cut portion 18 of sealing material.