The Conservation Minister has ordered a report into the deaths of another 21 kiwi chicks at the country's largest privately owned wildlife park - Cape Sanctuary in Hawke's Bay.
An earlier report into the death of nine little spotted Kiwi during the summer of 2016-17 found there was inadequate monitoring and pest control.
The deaths of another 21 brown kiwi chicks, in another part of the sanctuary that same summer, are confirmed in the 2016-2017 annual report by the Forest Life Restoration Trust, which provided the eggs.
In total, 43 chicks from the trust were sent to Cape Sanctuary for the 2016-17 season, but nearly half died.
"Dry conditions at the Cape this summer resulted in only 22 of these surviving through to release weight, the worst survival rates of crèched Maungataniwha chicks to date," the report said.
"The loss also has a real cost in financial terms, with each chick released to the wild costing a minimum of $3000 each. Therefore the loss represented a real cost to the Maungataniwha Kiwi Project of around $63,000."
"The only positive outcome from this positive episode was the firm commitment by Cape staff to avoid such losses in the future," the report said.
Forest Life Restoration Trust declined to comment on the losses.
Conservation Minister Eugenie Sage said she had received some information about the nine little spotted kiwi deaths and, after being alerted by RNZ to the 21 brown kiwi deaths, was now awaiting on another report from the Department of Conservation (DOC).
"I have made it clear to DOC that I want to be informed about such cases and expect best practice around care and monitoring to be met," Ms Sage said.
Emails released to RNZ under the Official Information Act show DOC staff were made aware of 10 possible brown kiwi chick deaths in March 2017 but it was unable to confirm whether the kiwi had died or were just missing.
The sanctuary was required to report any kiwi losses to DOC as part of its permit to hold the birds.
This month, following another OIA request, DOC confirmed it had only become aware of the deaths "quite recently."
"We continue to maintain close contact with Cape Sanctuary and monthly audits are taking place. A stronger working relationship with staff on the ground and better management practices will mitigate any future risk," DOC Hawke's Bay operations manager Connie Norgate said.
"In times of drought Cape Sanctuary may need to check chicks more often and this is being considered for this summer," she said.
Cape Sanctuary had improved its monitoring and pest control since the 30 kiwi deaths during the 2016-17 summer season. An internal progress report shows it had one of its best seasons for kiwi last summer with 33 North Island brown kiwi chicks being transferred from Rainbow Springs, with the loss of just five chicks.
Since its inception 85 percent of brown kiwi chicks transferred to the sanctuary's crèche have been returned to protected forest at Maungataniwha.