In explanation, ARPHS medical officer of health Dr Denise Barnfather said there was a risk children would leave the lodge and enter the drop area, and a further risk that the public would mistakenly believe the park was open due to their activities and enter the drop area.
During an earlier drop in 2015, the lodge was allowed to stay open on the condition that residents stayed within the property, but the court heard students were later found wandering into the drop zone.
Chris Browne, the lawyer representing Auckland Regional Public Health Services, said the students were "all over the place, outside the area they were understood to be".
Representing the lodge, lawyer Ryan Marsich said the order to close was unreasonable given the lodge's proposed safety plans to keep kids out of the drop zone.
Disadvantaged Māori and Pasifika students were booked in for activities and closing the lodge would have significant impacts on their mental wellbeing, he argued.
"Attendance would plainly be a positive experience for them," Justice Moore said in his decision released today, saying there will likely be adverse impacts to students unable to attend the lodge.
"I immediately recognise that it is both regrettable and unfortunate."
But he said these impacts were mitigated by the short closure period - about five days for the drop, and clearing the tracks of uneaten bait and predators' carcasses thereafter.
Justice Moore ruled that the ARPHS medical officer had followed the guidelines in requiring the lodge to close, and was under no legal obligation to consult the lodge on the 1080 drop.
The lodge owners' claims that the order to close was unreasonable and given at short notice were weak, the judge said.
A drop between now and late October was required to account for the upcoming bird breeding season, the need for specific weather conditions and to avoid school and public holidays.
"The combination of these factors means that delay would risk the whole operation failing," the judge said.
Delay would also cost the council and therefore ratepayers, with almost half the $900,000 of the operation cost already spent.
These significant negative repercussions meant public interest outweighed "by some considerable margin" the lodge's interest in staying open for students, Justice Moore said.