The chemical composition of a Tasmanian collection of the marine bryozoan Amathia wilsoni Kirkpatrick (Vesiculariidae) has been investigated previously and a series of brominated alkaloids, amathamides A-G were isolated. In a survey of the chemical composition of New Zealand marine bryozoans, we undertook an investigation of an extract of a New Zealand collection of A. wilsoni. We report here the isolation and structural elucidation of six novel alkaloids, amathaspiramides A-F (1-6), from this bryozoan. Amathaspiramide A (1) was acetylated to produce amathapiramide A monoacetate (7). An X-ray crystallographic structural determination of amathaspiramide F (6) revealed it to be an epimer of amathaspiramide C (3). Data from a singlecrystal X-ray diffraction study of amathaspiramide F (6) and those from NOESY NMR experiments were used to infer the absolute configuration of the amathaspiramides. The biological activity of this series of alkaloids was investigated.