New Zealand's Security and Intelligence Service (NZSIS) has been found to be "very intrusive" in some of its requests to banks for customers' information.
The spy agency watchdog, Inspector-General of Intelligence and Security Cheryl Gwyn, has released a report on a three month assessment of the service's policy and practices of acquiring personal information from banks.
She found that despite using voluntary disclosure requests, rather than getting official warrants to obtain the information, the voluntary aspect wasn't always made clear.
"Some of the past collection by the NZSIS would have constituted unreasonable searches contrary to the Bill of Rights," Ms Gwyn said.
The law was changed last year with the enactment of the Intelligence and Security Act 2017, which has resolved some of the issues identified, she said.
The period surveyed was three months at the end of 2016/17, and there was a different law then under which the NZSIS would apply for warrants and volunatary disclosures. It looked at 13 case studies within the period.
However in a report released yesterday Ms Gwyn criticised the lack of information the NZSIS is providing in its applications for warrants under the new law.
Ms Gwyn said the NZSIS was still not applying some of the requirements for disclosure in applying for warrants and in this case for voluntary disclosures.
It was probably an issue of interpretation, which she expected to be addressed the longer the new law is in place.
The NZSIS said it accepted the recommendations made by the Inspector-General and has either implemented them under the new Act or is working to implement them.
"NZSIS values the constructive working relationship we have with financial service providers. We couldn't do our work to protect New Zealand's national security without the assistance we receive," Director-General of Security Rebecca Kitteridge said.