A rise in syphilis cases has prompted renewed calls for people to practise safe sex, including the use of condoms.
The bacterial infection, which is usually sexually transmitted but can also be spread from mother to baby during pregnancy or birth, has been increasing in New Zealand since 2012.
Provisional data from the Institute of Environmental Science and Research indicated cases reported in 2017 had more than doubled since 2015, with 470 reported.
Auckland and Wellington men aged 20 to 39, especially those aged between 25 and 29, reported the highest number of cases. Seventy per cent of those affected were men having sex with men and almost 21 per cent were also HIV positive.
While homosexual men were the group most affected by syphilis, there had also been an increase in cases with heterosexual men and women.