Cases of syphilis have hit a record high in Auckland, quadrupling from previous years, new research has found.
The paper published in today's New Zealand Medical Journal - titled Auckland: City of syphilis? - said the significant increase was a worrying trend, particularly due to under-reporting.
Study author Dr Sunita Azariah of Auckland Regional Sexual Health found the service's clinics treated 152 cases of infectious syphilis last year - the largest number ever, and a 78 per cent increase from 2014.
She said the paper aimed to raise awareness of the sexually transmitted infection (STI), and how important it was for all sexually active people be tested for it.
"We need more resources to manage this issue. It's not a condition that's well recognised. A lot of health practitioners have probably never managed it until quite recently.
"It was a very common condition up until the end of the Second World War but with the discovery of penicillin and access to effective treatment the numbers went down considerably."
As in previous years, most cases were male, particularly gay and bisexual men.
"It's a trend that needs to be watched and public health action needs to be taken to try contain the outbreak before it spreads too much further," said Azariah.
The infection could become impossible to treat, according to research at the University of Zurich, which found 90 per cent of syphilis samples analysed were resistant to antibiotics.
Azariah said treatment of the STI was not well taught in medical school and doctors needed more training.
"Syphilis is a serious sexually transmitted infection. It has some potentially serious consequences, including brain and heart complications.
"Up to half of cases don't have any symptoms."
The findings come after Auckland District Health Board proposed to cut the number of specialists by a third to save costs.
Sexual health specialist Dr Rick Franklin told Radio New Zealand last week that the DHB plans to reduce the number of specialists, while increasing the number of nurses.
Franklin said this was a foolish move given the rapid rise in cases of syphilis and that those most vulnerable to sexually transmitted infections would be the worst affected.
Green MP Julie Anne Genter said last week the health system needed the tools to respond to STIs at a time they were booming.
"People with STIs need to have confidence that our health services are well-equipped to diagnose and treat the condition as well as to assist with notifications of partners.
"Right now, that simply isn't the case."
The DHB was consulting on the issue and no decisions had been made yet, Radio New Zealand reported.