Millions of private details are being swapped between government agencies, including names, birth dates, incomes, IRD numbers, citizenship details, travel plans, ACC claims, home addresses and phone numbers.
The move to add more lines to the web of data sharing and matching 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 risks that go far beyond passing on a missing father's address.
"There is the problem of controlling access. The greater the number of people who have eyes on it [private information], the greater the chance of it being improperly disclosed," said Michael Bott, lawyer and a member of the New Zealand Council of 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 of which have been operating for 20 years.
But the Government decided it needed to be able to set up such arrangements more easily, and altered 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.
From this year, hospitals have been able to check citizenship details under a data matching agreement with the Department of Internal Affairs. A previous crack-down on the $30 million annual bill for foreign patients getting taxpayer-funded medical care had offended some patients who were forced to produce a birth certificate or passport.
The first information-sharing deal under the new guidelines, which came into effect last week, allows the Department of Internal Affairs to share contact details with Inland Revenue. It will mean Kiwis living overseas, who haven't paid taxes, child support payments or student loan repayments, and apply to renew their passport will be contacted through the address they provide.
Other factors have been the growth of technology and concern for the vulnerable, including children. Agencies can now share personal information at an earlier stage when it is deemed there is a serious threat to public safety.
Following the death of 3-year-old Nia Glassie, Ms Shroff called for the sharing of information about at-risk children between authorities, and for "privacy" not to be used as an excuse or obstacle.
When drawing up information-sharing agreements, agencies must consult the Privacy Commissioner. The Office of the Privacy Commissioner at present has indications of 32 potential agreements, including areas such as dealing with offenders and sex offenders, restorative justice and the detection of serious crime.
A spokeswoman said it was important to note that not all the agreements discussed would come to fruition.
Those that do will come with risks. Breaches have included the Treasury's loss of a CD containing personal and company tax details in 2009, after it was mailed to Inland Revenue against protocol.
Other risks include the sharing - and resulting entrenchment - of inaccurate information across multiple databases.
"I can remember being told by my Canadian colleagues that they had an example where they got two people mixed up, in terms of their superannuation contributions, and that error compounded itself across multiple agencies, and in the end was impossible to unwind," Ms Shroff said.
"That's the sort of thing that keeps us on our toes."
Mr Bott said he had dealt with cases where isolated pieces of official information had been shared and taken together to create a misleading profile of a person.
"I've seen examples with Winz files where something completely innocent is blown out of proportion or is totally incorrect.
"And yet, once it is recorded, that information develops a permanence and longevity that becomes very hard for an innocent party to rebut or correct."
There is also debate about whether some sharing is ethical or appropriate.
This month the Herald reported that the Privacy Commissioner was consulted on the possibility of using identification numbers attached to preschoolers to help police beneficiaries.
New obligations require beneficiaries to take reasonable steps for their children to attend early childhood education from the age of 3, or have their benefits cut.
The Government has assured the industry there are no plans to progress the scheme, after providers threatened to boycott collecting attendance information, saying such sharing would damage their relationship with the most vulnerable families. Justice Minister Judith Collins said that the Government recognised the increased risks of information-sharing, but stressed there were checks and balances in place to ensure privacy was protected.
"I think New Zealanders can see clear benefits of these agreements ... [which] can't restrict New Zealanders' rights to get information about themselves and request correction of that information."
The Cabinet is soon to decide on what those organisations leading the new information-sharing arrangements would be required to publicly report. The Office of the Privacy Commissioner can also review an approved sharing agreement after 12 months and recommend it be changed or scrapped entirely.
It will also field complaints.
Ms Shroff said she was confident new information-sharing was balanced by robust and tailor-made safeguards.
She was also well aware of the stakes.
Three information-matching agreements
Customs/Inland Revenue Student Loan Interest Programme
Purpose: To detect student loan borrowers who leave for or return from overseas so that Inland Revenue can administer the student loan scheme and its interest-free conditions.
Year commenced: 2007
Features: Data transferred in near real-time by online transfer.
Inland Revenue disclosure to Customs: Inland Revenue provides Customs with the full name, date of birth, and IRD number for student loan borrowers who have a loan of more than $20.
Customs disclosure to Inland Revenue: For possible matches to borrowers, Customs provides the full name, date of birth, IRD number and date, time and direction of travel.
2011/12 activity: There were 485,464 borrower records (441,206 last year) updated as a result of matching student borrower records with travel movement information held by Customs.
Customs/Ministry of Social Development Arrivals and Departures Programme
Purpose: To identify current clients who leave for or return from overseas while receiving income support payments, and to assist MSD in the recovery of outstanding debts.
Year commenced: 1992
Features: Data is transferred weekly by online transfer.
Customs disclosure to MSD: Customs provides arrival and departure information covering the week prior to the extract date. Each travel movement record includes the traveller's full name, date of birth, gender, travel document number, country code and flight details.
2011/12 activity: 197 debtors under arrangement to pay. I35 debtors paid in full. $98,015.25 recovered.
Births, Deaths and Marriages/NZTA Deceased Driver Licence Holders Programme
Purpose: To improve the quality and integrity of data held on the Driver Licence Register by identifying licence holders who have died.
Year commenced: 2008
Features: Data transferred fortnightly by online transfer.
BDM disclosure to NZ Transport Authority: BDM provides death information for the fortnight prior to the extract date. The death details include the full name (current and at birth), gender, date and place of birth, date of death, home address and death registration number.
2011/12 activity: 29,772 records received for matching, 16,641 driver licence records cancelled.
