Tests for firefighting foam contamination are going to take place at the Woolston fire training centre in Christchurch.
Woolston would be the first fire training site to have tests run across soil, sediment and surface water and groundwater samples, Fire and Emergency New Zealand (FENZ) said.
It's the only site out of more than 660 that the agency has done a desktop check of, while a more detailed investigation is to take place into PFAS pollutants which last thousands of years and accumulate in people's livers.
Consultants had recommended they "conduct a detailed site investigation involving sample and analysis of soil, sediment, surface water and groundwater at the Woolston site", FENZ said in a statement.
Planning was underway, it said.
Another seven fire training sites were still being looked at in various parts of the country, after screening of the 660 sites resulted in 115 getting an initial assessment, and just eight of those hitting the threshold for a preliminary site investigation.
At one of those eight, Hastings - which has 57 water bores within a 1km radius - recent tests by Hawke's Bay Regional Council had been done, FENZ said.
"This included the back-up water bore at Hawke's Bay hospital. No detectable PFAS was found in any of the samples.
"We consider that this engagement with the regional council demonstrates that a precautionary approach is being taken by Fire and Emergency.
"None of the other [seven] sites ... have indicators that might warrant early sampling."
The nationwide investigation of contamination most closely linked to now-banned foams once widely used by fire brigades at civilian and military airports and petrochemical plants has been scaled back since the Defence Force finished its testing some months ago.