A search warrant led by Waikato Regional Council was executed at a construction and demolition landfill site at Pukemiro, south-west of Huntly, yesterday morning.
Any information gathered will form part of an ongoing investigation by the council into possible breaches of the Resource Management Act (RMA) at the Puke Coal Ltd site.
Last month a health notice was issued to the residents of Pukemiro, asking for pregnant woman and breastfeeding woman to move out of the area due to a fire burning on a dump site. That notice was lifted at the start of December with no risk found.
Council regional compliance manager Patrick Lynch said 23 people are involved in the "very detailed scene examination", which is expected to take up to two days.
"We are completely open minded as to what activities have been occurring on site. This search warrant is simply a regulatory agency working to establish the truth of what has happened here," Lynch said.