The country's spy agencies failed to provide more than 100,000 internal emails to an inquiry into controversial New Zealand operations in Afghanistan.
The country's spy watchdog, the Inspector-General of Intelligence and Security (IGIS) Cheryl Gwyn, has reported ongoing struggles to be given access to staff emails and attachments from the agencies, even though she is legally empowered to see these.
"The IGIS's right to directly access these records was initially called into question by the agencies, but eventually resolved," she said in an inquiry update.
"Nonetheless, the challenge of accessing all relevant staff emails has remained a recurring point of difficulty."
Ms Gwyn asked for access to the mailboxes of specific staff early last October.
She is conducting an inquiry running alongside to one ordered by the government into allegations the Defence Force covered up the deaths of six civilians in the New Zealand-led Operation Burnham in Afghanistan in 2010.
The Inspector-General got access to several tens of thousands of emails in January this year.
But it was only when her office reviewed these they made a surprising discovery.
"The review process for these emails revealed certain anomalies in the document production process, affecting principally the GCSB [Government Communications Security Bureau]," Ms Gwyn said.
"The IGIS team spent considerable time pursuing these issues. Our efforts resulted in the GCSB in May 2019 locating and producing over 115,000 additional staff emails for our review, being emails previously left out of the document production process due to an oversight."
This is an eight-month period between the IGIS asking for the information, and her getting it.
She was now seeking independent technical advice to help her inquiry understand the problems with getting the information.
"The inquiry team has met with the bureau [GCSB] to satisfy itself about the search methodology used and the technical reasons for some anomalies in the results."
Some of the extra emails would also be relevant to the government inquiry, she said.
GCSB Director-General Andrew Hampton and SIS Director-General Rebecca Kitteridge were both unavailable for an interview.
Mr Hampton in a statement said his agency was "as always", working "actively and constructively" with Ms Gwyn.
The GCSB's email repository contained historic archived material which "requires significant time to restore and make available to the Inspector-General to search".
"As the Inspector-General acknowledged in her update, the second tranche of historic emails was a genuine oversight and we worked constructively with the Inspector-General to address this matter," he said.
"The second tranche contained duplications of material already made available to the Inspector-General as well as some new material.
"I understand that the Inspector-General is still reviewing the second tranche of emails and it is likely only a small proportion will be relevant to the inquiry."
Ms Kitteridge said the SIS welcomed the Inspector-General's oversight.
"We service her requests as quickly as we can, while balancing operational needs," she stated.
"Some issues require quite a lot of discussion and we work through them with all parties working for the best outcome for New Zealand."
Public hearings have been running as part of the Operation Burnham inquiry, that is investigating allegations in the book, Hit and Run.
The Defence Force denies the allegations.
Ms Gwyn said the official records that were key to her inquiry were "often in the form of staff emails, or attached to emails, and remain stored in individual staff email accounts, rather than in a central organisational record system".
She is due to publish an unclassified report of her inquiry next month.
The GCSB and SIS have been approached for comment.
- 5 October 2018 - Cheryl Gwyn asks for email re Afghanistan operations from SIS and GCSB
- December - Gets limited access to some "critical record systems"
- January 2019 - Gets access to tens of thousands of staff emails
- February - March - Gets access to some other security records
- May - The watchdog discovers anomalies, resulting in 115,000 emails not released in January, being released by GCSB