Objectives Over the last decade, annual HIV diagnoses among men who have sex with men (MSM) in New Zealand increased, then stabilised in 2006 and have not increased further. The aim was to examine trends in behaviours in order to better understand this pattern and inform community-based prevention.

Methods From 2002 to 2011, we conducted five repeat cross-sectional behavioural surveillance surveys among MSM at community locations in Auckland (fair day, gay bars, sex-on-site venues; n=6091). Participation was anonymous and self-completed. Recruitment methods were consistent at each round.

Results Overall, the samples became more ethnically diverse and less gay community attached over time. Condom use during anal intercourse was stable across three partnering contexts (casual, current regular fuckbuddy, current regular boyfriend), with a drop among casual contacts in 2011 only. In the 6 months prior to surveys, there was a gradual decline over time in the proportion reporting >20 male partners, an increase in acquiring partners from the internet and increases in engagement in anal intercourse in some partnering contexts. HIV testing in the 12 months prior to surveys rose from 35.1% in 2002 to 50.4% in 2011, mostly from 2008.

Conclusions This first indepth examination of trends in HIV-related behaviours among five consecutive large and diverse samples of MSM in New Zealand does not suggest condom use is declining. However, subtle changes in sexual networks and partnering may be altering the epidemic determinants in this population and increasing exposure.