Public health officials pulled out of telling people about firefighting foam contamination in a dispute over what to say about the risks, newly released emails show.
Nelson-Marlborough's public health unit officials were meant to go door-knocking to provide reassurance to locals over the PFAS contamination, visiting residents around Woodbourne airbase.
The PFAS class of chemicals - of which PFOS and PFOA are banned in New Zealand - accumulate in the body over time. They are increasingly linked in overseas studies to environmental and health risks.
The groundwater around several defence bases have been contaminated with toxic and long-lasting firefighting foam chemicals.
However, the emails newly released to RNZ under the Official Information Act showed the health unit suddenly pulled out of doing the visits.
This came early last December, the day before the Defence Force went public for the first time about the foam contamination.
"It is very unfortunate it has come to this, but the [unit] is very firm that it cannot send its staff into the field with so little information about the risk assessment for the area," a Health Ministry official wrote on 6 December.
"Their role is to protect public health and they consider they lack the information necessary to provide definitive advice," the email said.
The ministry countered that "our view is that there is sufficient information in the fact sheet to advise the households".
The ministry said it did not agree that the information was inadequate, but the staff never went out.
The contamination investigation has since widened to include airports, fire brigade training areas and industrial sites within the territories of 16 regional councils.
The US Agency for Toxic Substances has previously said the effect of the chemicals was not certain but it could increase the risk of cancer, decrease fertility and cause problems with fetus development.
The Ministry of Health's advice since December is that there is no conclusive evidence of long-term health damage from ingesting the PFOS or PFOA left in the water or soil from firefighting foam. This is very similar to Australia's official advice.