Reported cases of rheumatic fever have risen despite the Government investing millions to tackle the disease.
A survey conducted by the Institute of Environmental Science and Research recorded 235 reported cases of rheumatic fever in the year to September 2014, up 75 on the previous 12 months.
The Government has committed $65 million to help reduce New Zealand's high rates of rheumatic fever which particularly affects Maori and Pacific children.
The head of the Ministry of Health's Rheumatic Fever Prevention Programme, Dr Chrissie Pickin, said the latest ESR survey was not a good measure of the programme's success.
"What this data is showing is an increase in cases reported from one year compared to the other, which is not the same as an increase in the number of cases diagnosed in one year, compared to the other."
The ministry says it prefers to focus on the number of [ http://www.radionz.co.nz/news/national/260719/rheumatic-fever-changes-'scary' people hospitalised] with new cases of rheumatic fever.
Auckland University child population health expert Professor Diana Lennon agrees hospitalisation rates are a better measure.
She said latest data from hospital admissions contained some positive results.
"Excitingly the numbers of cases in the eye of the storm if you like, South Auckland, over the last quarter of 2014, have shown an amazing reduction."
Green Party health spokesman Kevin Hague remains critical of this rise in reported cases.
"Any of this increase that reflects better detection of the disease is actually saying something pretty grave as well, because it would be saying that the underlying rate of this disease in New Zealand, the prevalence of this disease, is even worse than we thought it was."
The Ministry's programme tackles rheumatic fever in three ways.
It aims to have children with the precursor, strep throat, treated earlier, and runs awareness campaigns focused on the disease.
It also runs healthy homes initiatives to try to reduce household crowding, known to create a breeding ground for infections.
Mr Hague is not convinced enough is being done to address the root causes of the problem - child poverty and damp housing.
The Ministry of Health said it is too early to say whether the programme is a success but the question of whether it is making any inroads will be answered when new hospitalisation data comes out in the next few months.