On Wednesday, 18 kākāriki karaka (orange-fronted parakeets) were transferred from aviaries in Christchurch and released into Lake Sumner Forest Park, Hurunui.
The endangered birds were due to be released several weeks ago.
Their release became urgent for the welfare of the birds and to free up "much-needed" space in the aviary.
Minister of Conservation Eugenie Sage said it was a great marker of success for the population of this "budgie-sized" native bird.
"The orange-fronted parakeet are a taonga species for Ngāi Tahu.
"Releasing birds into the wild is a vital part of the recovery plan for this critically endangered species," she said.
The Department of Conservation is working with Ngāi Tahu, the Isaac Conservation and Wildlife Trust and Christchurch Helicopters to transfer the birds following strict Covid-19 protocols.
"Monitoring before the lockdown showed the birds released last month teamed up with wild kākāriki," said Ms Sage.
"DOC is hoping this new group of birds does the same."
The rarest of New Zealand's six kākāriki species, the orange-fronted parakeet is only found in Arthur's Pass National Park and the Hurunui South Branch in Lake Sumner Forest Park.
"Christchurch Helicopters' practical assistance with the recovery programme and raising additional funds is much appreciated," said Ms Sage.
"I want to acknowledge the tremendous work and the expertise of the Isaac Conservation and Wildlife Trust in the success of the programme and providing essential wildlife services during the lockdown."
