The operation would see the poisonous 1080 bait, a biodegradable poison called sodium fluoroacetate, dropped by helicopter over the regional park where the 82-bed Kōkako Lodge sits on the foothills.
Lawyer Ryan Marsich said the order to close was "unreasonable" given its proposed safety plans aimed at minimising the risk of lodge residents entering the drop zone.
Disadvantaged and vulnerable youths were booked in for activities during this period and closing the lodge would have significant impacts on their mental wellbeing, he said.
Many of them were part of a Ministry of Education programme called Aim High, which focuses on decile one schools with low attendance.
"These students face significant challenges and were particularly affected by the Covid-19 pandemic and its repercussions," he said.
The lodge had proposed a safety plan where activities during the drop would be confined and students would not go beyond the lodge boundaries or take part in water activities.
There would also be two adults - one instructor and one teacher - for every group of 10 students to ensure compliance, Marsich said.
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 Brown, the lawyer representing Auckland Regional Public Health Services, said the students were "all over the place, outside the area they were understood to be".
Auckland Council lawyer Lizzy Wiessing said the lodge was occupying council land under a licence - not a lease - which came with conditions on the use of the land.
Communications about the bait drop started late last year - around the time these bookings were taken - so the lodge should have expected they would need to close at this time, she said.
But the lodge argued the actual notice to close was only sent on August 24 which was "very late" and a complete surprise.
Marsich had asked the court to issue an interim order for the lodge stay open while the 1080 drop went ahead with adjustments.
"This is not an all or nothing operation," he said. "The operational area of the drop is some 20,000ha, the lodge is only a small part of it."
He said two other camps in the area were not required to close even though one of them, the Hunua Falls Camp was about 300m from the drop zone, similar to Kōkako.
Wiessing told Open Justice this was because the two properties were not in park land and therefore not subject to conditions.
In court, she acknowledged the work of the lodge but argued there was public interest in the health of the park.
Forty per cent of the cost of the operation had already been committed; the bait had been bought and could not be resold or easily disposed of.
Wiessing said the Council had tried to accommodate the lodge's concerns and long discussions were had but they could not accept all the safety plans.
Closure conditions this year were less onerous - five days and up - compared with the four weeks in an earlier, 2018 operation.
The 1080 drop is currently scheduled for the next available weather window. "[Council is] watching the weather like a hawk," Wiessing told the court.
