An accumulating portal conveyor comprises a conveyor belt, a frame for supporting and guiding the belt, which frame includes a first helical path and a second helical path spaced from the first helical path, a bridging path and a return path. Under operating conditions the belt successively follows the first helical path upwardly, the bridging path, the second helical path downwardly and the return path, and such that in transverse direction of an upright plane through central centerlines of the first and second helical paths. The bridging path includes a static part having a fixed position with respect to the helical paths and a dynamic portion displaceable in transverse direction of the upright plane to change the path length of the belt. At least a portion of the return path is displaceable for compensating the change of the path length of the belt at the bridging path.