Parliament's health select committee has raised concerns about the growth of syphilis in South Auckland and the need for extra funding for primary and sexual health services to stop its spread.
At least one leading academic says there's also a need for more up-to-date data and contact tracing to get on top of the disease.
Syphilis is a sexually-transmitted infection that can be treated and cured with antibiotics. If it isn't treated however, it can over time affect the brain, spinal cord and other organs.
The select committee released a report last month as part of its 2019/2020 annual review of the Counties Manukau DHB. It said 40 percent of syphilis cases in New Zealand were in the Counties Manukau area.
"Counties Manukau DHB told us that extra resourcing for primary care would be key to reducing the incidence of syphilis, and other reproductive and sexual health issues," it said.
"Greater resourcing for the Auckland Regional Public Health Service, which has had to divert substantial focus to Covid-19 response in the last year, would also contribute to helping tackle infectious diseases in the area."
The most up-to-date data released by the Institute of Environmental Science and Research (ESR) this month is from 2019 and shows a noticeable jump in recorded cases of syphilis nationally, from 629 in the 12 months to December 2018 to 727 in December 2019.
The recent New Zealand Paediatric Surveillance Unit's Annual Report 2019-2020 highlighted the impact of congenital syphilis in South Auckland, where a woman infected with the condition passes it onto her unborn child.
It cited a study between April 2018 and June 2020 which found of the 30 recorded cases of children with the condition nationally, all of them involved newborn infants and 10 of the cases were recorded by the Counties Manukau DHB.
University of Auckland's medical and health sciences senior lecturer in population health Peter Saxton has completed research on the control of sexually-transmitted diseases and said it was hard to find solutions and to stop the spread of conditions like syphilis if the people and organisations dealing with it did not have up-to-date statistics to work from.
"We've been working with old stats for several years now. We don't know where to make interventions if we don't have up-to-date data," Saxton said.
He said it would be difficult to interpret the data from 2020 when it was released because the pandemic had impacted on the ability of people to get tested and access sexual health services.
Saxton said there was a noticeable jump in the number of cases of syphilis nationally from 2018 to 2019.
"It's not a new problem, but it's getting worse," he said.
Saxton said poverty and poor access to primary healthcare services were a key factor in the spread of communicable diseases like syphilis in areas like South Auckland.
He said the DHBs and the Ministry of Health needed to look at how they were fighting the disease and what they were doing to stop its ongoing spread.
"If it's congenital syphilis how are we implementing our pregnancy screening guidelines? How accessible are sexual health services and what about contact tracing?
"Covid-19 has shown us, with the political will and investment we can have a gold system of controlling the spread of infectious diseases," he said.
"But we need some more transparency."
A spokesperson for ESR said it was still compiling its syphilis data from 2020 and it was not ready to be published.
They said the release of the statistics had been delayed due to resources being redirected to the Covid-19 response.
In a statement, a Ministry of Health spokesperson said the institute remained the lead agency in New Zealand undertaking syphilis surveillance.
"ESR is continuing to collate the latest data and we expect this will be available within the first half of this year."
The ministry spokesperson said clinicians were required by law to report all cases of syphilis to the Crown research institute under the Health Act 1956.
According to the Ministry of Health, syphilis has been increasing in New Zealand since 2012 - particularly in men who have sex with men - but infection rates in heterosexual men and women have also been increasing which has led to an increase of congenital syphilis.
The first sign of the condition is often a sore or ulcer (called a chancre), which usually appears about three weeks after infection and can last between three and six weeks before it heals, with or without treatment.
Someone who does not get treatment remains infectious.
If the disease is left untreated it will progress to the next stage where symptoms include rashes, often with red or brownish spots on the palms of the hands and soles of the feet.
Other symptoms include swollen lymph glands, fever, hair loss, muscle and joint aches, headaches, tiredness, and warty growths in skin folds.
If it isn't treated a small number of people will get late stage tertiary syphilis years after the initial infection which can cause damage to the heart, brain, nerves, eye, blood vessels, liver, bones and joints.
Counties Manukau DHB and the Auckland DHB (ADHB), which runs the Auckland Sexual Health Service, were contacted for this story.
The Auckland Sexual Health Service is funded by the Counties-Manukau, Auckland and Waitematā District Health Boards.
Local Democracy Reporting is a public interest news service supported by RNZ, the News Publishers' Association and NZ On Air.