Background: The National Heart Foundation of New Zealand perceived a need to support non-nutritionally trained primary care practitioners providing nutrition counselling to patients with or at risk of cardiovascular disease. A brief dietary assessment tool was commissioned. Objective: This study aimed to determine how a brief dietary assessment tool should be designed for use by practice nurses in New Zealand with the intention of providing individualised nutrition advice to reduce individuals' risk of cardiovascular disease (heart healthy eating counselling). Areas investigated were 1) current state of heart healthy eating counselling provided by practice nurses in New Zealand; 2) needs and preferences of practice nurses in relation to design of a brief dietary assessment tool; and 3) key dietary behaviours related to heart health of New Zealanders with or at risk of cardiovascular disease.Design: An action research approach was used as the underlying strategy of inquiry for the study. Two data collection methods were used to achieve objectives: semi-structured interviews and secondary data analysis of the 2008/09 New Zealand adult nutrition survey. 11 practice nurses from the Auckland region were recruited for the interviews, and their responses were analysed using the general inductive approach to develop recommendations for design of the brief assessment tool. Secondary data analyses ranked dietary behaviours against level of evidence for effect on cardiovascular disease and evidence of it being a main problem dietary behaviour in New Zealanders' dietary pattern to identify evidence-based and setting-appropriate question topics for the brief assessment tool.Results: All of the participants felt there were constraints on their ability to provide effective heart healthy eating counselling. Major constraints reported were time and patient attitude. Variable dietary assessment methods and sources of nutrition advice were also found. In terms of design aspects of the brief assessment tool, participants preferred a paper-based tool with good visual impact that should be quick to administer (5-20 minutes, 5-20 questions). Participants also felt that the assessment structure should be simple and allow quick identification of dietary behaviours to target for heart healthy eating counselling. From the secondary data analyses of the New Zealand adult nutrition survey, ten key dietary behaviours relevant to heart health of New Zealanders were identified for inclusion as question topics in the assessment tool: choosing low- or reduced-salt options, fruit intake, adding salt after cooking, fish intake, convenience food intake, vegetable intake, type of milk consumed most, processed meat intake, type of spread used most and type of bread consumed most.Conclusion: The study findings indicate that there is a real need to support practice nurse-provided heart healthy eating counselling in New Zealand. It is recommended that a brief heart healthy eating assessment tool be designed as follows to optimally support practice nurses: paper-based, colour-coded response criteria, pictorial examples, 5 minutes to administer, brief scored questionnaire with 10 questions taken from secondary data analyses. It is also recommended that ethnic-specific versions of the tool be developed for Māori, Pacific Island and South Asian patients who are at higher risk of cardiovascular disease.