Macrobenthic community structure was assessed on intertidal sandflats, a predominant feature of Manukau Harbour. Thirty‐six replicate core samples were collected from each of six 9000 m2sites, during October 1987. The distribution of individuals amongst taxa was similar at the six sites, but the numerical dominance of the most common taxa changed appreciably from site to site. A shift from polychaete‐ to bivalve‐dominated communities was apparent between sites. Examination of a hypothesised relationship between sediment grain size and trophic structure of the macrobenthos highlights the difficulties in using this relationship to monitor environmental change. Identification of core taxa by DECORANA ordination and TWINSPAN classification is considered a useful mechanism in defining taxa likely to play major roles in influencing community structure and function.