The Inspector-General of Intelligence and Security has found no evidence of wrongdoing by the GCSB in relation to its intelligence gathering activities in the Pacific.
Cheryl Gwyn investigated claims made in 2015 that the agency had been intercepting the communications of New Zealanders working or travelling in the South Pacific.
The claims were based on documents released by American whistleblower Edward Snowden.
Ms Gwyn said the GCSB did carry out "signals intelligence-gathering" in relation to New Zealand's interests in the Pacific from 2009 to 2015 but it was all mandated.
"There were statutory authorisations in place enabling it to do so and the Bureau had policies and procedures in place to govern its foreign intelligence activities."
She did find two "inadvertent" breaches, but said they were detected and remedied.
Ms Gwyn found no evidence any of the complainants' private communications were deliberately targeted.
"It is possible that some of their private communications were collected by the GCSB, either using collection methods that inherently involved collecting some non-targeted communications, or if a complainant was communicating with a person or organisation who was being targeted.
"If that occurred, there is no evidence that GCSB retained any such data relating to any complainant," Ms Gwyn said.
"Somewhat unusually", she said, there were no recommendations as a result of the investigation because of the "lack of any adverse finding" in relation to the complaints.
"Also the report concerned GCSB activity under the Government Communications Security Bureau Act 2003, which has been superseded by the Intelligence and Security Act 2017 and a revised suite of Bureau policies", Ms Gwyn said.