The learning difficulties for new entrant chemistry students from a multi-national, regional, tertiary education institution in the South Pacific were investigated using a purpose-designed diagnostic instrument. The instrument contained 25 items distributed across three themes: scientific reasoning, numeracy and scientific language literacy. The research findings suggest that the main learning difficulty facing these students is in numeracy with students able to interpret numerical data presented in graphical form and to complete rudimentary numerical calculations, but unable to use numerical data or perform calculations involving ratios. Targeted remedial tutoring, based on the results of this diagnostic test instrument, rather than content-driven extra tutorials, are suggested for remediation of learning difficulties.