Millions of pieces of private information about New Zealanders are being shared between state departments - and the Government is planning to vastly increase the number of agencies involved, a Herald investigation has discovered.
The personal details already shared include names, birthdates, incomes, tax numbers, citizenship details, travel plans, ACC claims, home addresses and phone numbers.
View what information each government agency holds about you with this Herald infographic.
But the number of deals to share information about hundreds of thousands of Kiwis could increase by more than 50 per cent, with over 30 new agreements between agencies being explored.
Belt-tightening during tough economic times and inaction on child abuse cases are main drivers for the push to share more - and the Government insists it can be trusted to protect New Zealanders' privacy.
However, it comes during a low ebb in public confidence in government information handling, after several high-profile breaches.
Civil liberties campaigners, the Privacy Commissioner and the Government all recognise that increasing data matching and sharing agreements amplifies the room for error.
"There is the problem of controlling access ... the greater the number of people who have eyes on [private information], the greater the chance of it being improperly disclosed," said Michael Bott, a lawyer and member of the Council for Civil Liberties.
"And how do you rectify the information? If you have 20 or 10 government departments sharing it, and some information is incorrect, who do you go to? ... You get a ripple effect."
Information matching is the disclosure of personal information about an individual by one government agency to another. There are currently 56 active programmes, some 20 years old.
In order to set up such arrangements more easily, the Government has now altered the information-sharing provisions in the Privacy Act.
Privacy Commissioner Marie Shroff, whose office gave its approval to the new provisions and will play a vital watchdog role over them, said there were important reasons behind the change. The recession had focused attention on how to conduct government business more efficiently.
Matching data has saved tens of millions of dollars.
The first information-sharing deal under the new guidelines, which came into effect last week, will mean Kiwis living overseas who haven't paid taxes, child support or student loan repayments can be tracked by the taxman through the address they give when they renew their passport.
Another factor is concern for the vulnerable, including children. After the death of Rotorua 3-year-old Nia Glassie, Ms Shroff called for the sharing of information about at-risk children, and for "privacy" not to be used as an excuse or obstacle.
Ms Shroff's office at present has indications of 32 potential new agreements. A spokeswoman said not all would come to fruition.
Those that do come with risks. The loss in Britain of two CDs containing records of 25 million child-benefit recipients has been cited as a reason for the limiting of proposals for wide information-sharing powers there.
In NZ, breaches have included the Treasury's loss of a CD containing personal and company tax details in 2009, after it was mailed back to Inland Revenue against protocol.
Justice Minister Judith Collins said the Government recognised the increased risks of information sharing, but stressed there were checks and balances in place to ensure privacy was protected.
"Across the public sector, New Zealanders will be provided with tailored, bundled services targeted to meet their individual needs rather than requiring them to deal with multiple agencies to get help with one or related issues."
The Cabinet is soon to decide what the agencies will be required to publicly report.