Background Behavioural interventions are often implemented within primary healthcare settings to prevent type 2 diabetes and other lifestyle-related diseases. Although smoking, alcohol consumption, physical inactivity and poor diet are associated with poorer health that may lead a person to consult a general practitioner (GP), previous work has shown that unhealthy lifestyles cluster among low socioeconomic groups who are less likely to seek primary healthcare. Therefore, it is uncertain whether behavioural interventions in primary healthcare are reaching those in most need. This study investigated patterns of GP consultations in relation to the clustering of unhealthy lifestyles among a large sample of adults aged 45 years and older in New South Wales, Australia. Methods A total of 267,153 adults participated in the 45 and Up Study between 2006 and 2009, comprising 10% of the equivalent demographic in the state of New South Wales, Australia (response rate: 18%). All consultations with GPs within 6 months prior and post survey completion were identified (with many respondents attending multiple GPs) via linkage to Medicare Australia data. An index of unhealthy lifestyles was constructed from self-report data on adherence to published guidelines on smoking, alcohol consumption, diet and physical activity. Logistic and zero-truncated negative binomial regression models were used to analyse: (i) whether or not a person had at least one GP consultation within the study period; (ii) the count of GP consultations attended by each participant who visited a GP at least once. Analyses were adjusted for measures of health status, socioeconomic circumstances and other confounders. Results After adjustment, participants scoring 7 unhealthy lifestyles were 24% more likely than persons scoring 0 unhealthy lifestyles not to have attended any GP consultation in the 12-month time period. Among those who attended at least one consultation, those with 7 unhealthy lifestyles reported 7% fewer consultations than persons with 0 unhealthy lifestyles. No effect modification was observed. Conclusion To optimise the prevention of lifestyle-related diseases, interventions for positive behavioural change need to incorporate non-primary healthcare settings in order to reach people with multiple unhealthy lifestyles.