Objective: To determine the impact of a healthy food and drink policy on hospital staff and visitors' food purchasing behaviours, and their awareness and support for the changes introduced.

Design: Two repeated cross-sectional surveys, consisting of intercept interviews and observations of food items purchased, were conducted before (March-July 2018) and after (April-June 2019) the target date for implementation of thirteen food and drink practices (31 December 2018). Food purchases were coded as 'Everyday' (healthy) or 'Occasional' (unhealthy).

Setting: Ten randomly selected New South Wales public hospitals, collection sites including hospital entrances and thirteen hospital cafés/cafeterias.

Participants: Surveys were completed by 4808 hospital staff and visitors (response rate 85 %). The majority were female (63 %), spoke English at home (85 %) and just over half had completed tertiary education (55 %).

Results: Significant increases from before to after the implementation target date were found for policy awareness (23 to 42 %; P < 0·0001) and support (89 to 92 %; P = 0·01). The proportion of 'Everyday' food purchases increased, but not significantly (56 to 59 %; P = 0·22); with significant heterogeneity between outlets (P = 0·0008). Overall, younger, non-tertiary-educated adults, visitors and those that spoke English at home were significantly less likely to purchase 'Everyday' food items. Support was also significantly lower in males.

Conclusions: The findings provide evidence of strong policy support, an increasing awareness of related changes and a trend towards increased 'Everyday' food purchasing. Given the relatively early phase of policy implementation, and the complexity of individual food purchasing decisions, longer-term follow-up of purchasing behaviour is recommended following ongoing implementation efforts.