Arbuscular mycorrhizal fungi (AMF) are components of coastal dune ecosystems around the globe where they provide a range of benefits to plants. The diversity and structure of AMF communities within these ecosystems, however, are poorly known. This study presents the first report of an AMF community in a New Zealand dune. Root samples were collected from the grass Spinifex sericeus R. Br., which dominates dunes of the North Island of New Zealand, along a 90m transect. Spores were also collected. The AMF community within the roots was surveyed using 454 sequencing of the SSU gene region. The 22 operational taxonomic units recognised formed a phylogenetically diverse community, including at least 8 genera across the Glomerales and Diversisporales, with an additional genus detected by the spore investigation. Some root and spore derived sequences generated close BLAST matches to AMF from distant countries while others represent previously unknown biodiversity. Spore morphology also suggests undescribed AMF are present. The community was heavily dominated by the genera Rhizophagus and Racocetra, together with AMF from a clade with no matches to a described genus. Spatial heterogeneity was observed, with taxonomic composition changing over distances of only 30 m.