More than a third of the country's public lavatories have no soap and some even lack running water - a finding public health experts say could harm the country's reputation as a tourist destination.
The Otago University study, published in the New Zealand Medical Journal, is the first multi-region survey of public loos and the latest to highlight poor attitudes to hand hygiene.
Researchers surveyed 150 council-run public toilets in seven cities, 30 towns and 18 different local authority regions in the lower North Island.
They found 39.3 per cent of toilets had no soap and 4 per cent had no running water, with rural and minor urban areas worse off than cities.
Return visits to 51 of the facilities revealed no overall improvements in soap and water availability. Other issues included a lack of signage, doors that did not shut properly, a lack of cleanliness and automatic flush systems that did not work.
The study comes after an earlier survey of public toilet behaviour found 13 per cent of users did not wash their hands and 28 per cent did not use soap.
Otago University public health researchers Nick Wilson and George Thomson said the soap and water situation at many public toilets was inadequate from a public health perspective, both in terms of the spread of infectious diseases and pandemic preparedness.
"But sub-optimal provision of public toilets is also a concern in terms of New Zealand's reputation as a tourist destination."
They said councils had to meet limited requirements around cleanliness, but that was not enough to ensure all facilities had soap and water. The authors floated the idea of government funding to encourage minimum standards for public toilets, which they said would benefit both local travellers and visiting tourists.
Taranaki medical officer of health Greg Simmons, who helped undertake the earlier research on hand-washing habits, said good hand hygiene needed to be taken seriously.
"It's ... infection control 101, really," he said. "We should all be making sure that the facilities are optimal."
Dr Simmons said good hygiene helped to stop the spread norovirus, rotavirus and other forms of gastroenteritis. People needed to wash their hands for at least 20 seconds. Drying was as important as using soap.
"If you just wash your hands and have a wet hand surface, then everything you touch more effectively picks up bacteria."
The latest study suggested further research on hand-drying facilities was needed.
39.3 per cent of toilets had no soap
4 per cent had no running water
Rural and minor urban areas worse off than cities.