New Zealand shares travellers' private data with four other countries. Here's the story of how one reporter found out

How a reporter uncovered the story behind a secretive network sharing travellers' data.

Gill Bonnett always had a sense of an "invisible hand" operating above immigration policy. Her discovery of a Migration5 briefing document to the immigration minister several years ago confirmed it.

As RNZ's immigration reporter, she has spent several years poring over immigration files, refugee reports and asylum seeker applications, so spotting the M5 reference piqued her interest.

But she faced a lot of silence to her numerous questions, and her requests for more information under the Official Information Act were consistently blocked.

Her search took her across the world to Washington DC as a Fulbright scholar. While there she tracked down people who had been involved in the network from 2008, when it first started to share data about a few thousand asylum seekers.

Since then, the network of five countries - the US, UK, Australia, Canada and New Zealand - has built up its data sharing to millions of travellers, Bonnett found.

Last week Immigration Minister Erica Stanford described M5 as a long-standing agreement with no "particular secrecy around it".

But Bonnett encountered a high level of secrecy among the diplomats and officials she spoke to in Washington.

Her discussions with them were "entirely off the record". Only people such as lawyers, academics and civil rights campaigners were willing to share their concerns about individuals' privacy, lack of transparency, hacking risks and the dangers of making mistakes and ruining lives.

"I got the feeling that it was a group that didn't really want to be known," she says. "There was almost a feeling that they were playing at it, that they saw themselves as pseudo intelligence officers."

At the same time they defended M5 as the way ahead, an efficient way of stopping dangerous people from travel before they even got to the airport.

Beyond those she spoke to in Washington, Bonnett says it was incredibly difficult to find people who knew about the network.

"There is basically one expert who knows part of the jigsaw puzzle in each of the five countries. So we compared notes, we found a little bit more about the history of it but there's still quite a lot that we don't know."

Bonnett is still working to uncover more about M5, including the financial cost to New Zealand of being involved and the role of artificial intelligence. She says more transparency is important so that people know what information is being shared about them and how that information is used…

Go to this episode on rnz.co.nz for more details