People are being urged to take care in areas of the Hunua Ranges where toxic 1080 bait has been laid.
The Auckland Council said the first application of 1080 in the Hunua Ranges area was complete, and the parklands were expected to reopen later this week.
In the last few years, possum and rat numbers have increased significantly in the area, and this was having a severe effect on the health of the forest and threatened species, like kokako, that live within it.
To target these pests, 1080 bait was applied to a block of the 21,000 hectare area last Friday.
Another block was also treated, with non-toxic pre-feed bait to familiarise pest animals with the baits.