You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
The Inland Revenue Department had 32 privacy breaches involving the personal information of 6300 people being sent to the wrong person in the past year.
Revenue Minister Peter Dunne said 638 people affected by the most serious breach had been contacted because details like their addresses and tax numbers had been released.
Not all those affected by every breach would be contacted, however.
The biggest breach was down to human error.
Mr Dunne said he was not happy with any breaches and apologised to anyone whose information had been compromised.
"We deal with 25 million transactions a year so 32 breaches out of 25 million is a pretty small number, but one breach is too many," he said.
Labour's Revenue spokesman David Clark is calling on the Government to overhaul IRD's 20-year-old computer system.
He said the Government was not taking personal privacy seriously.
"Human error happens when systems are under stress - these things went out via email, they went out via printed out material in envelopes - those are the kinds of things computers are involved with.
"We know the system is 20 years old, it's 10 years older than Facebook, it's older than Google and older than the internet as we know it," Mr Clark said.
Mr Dunne has given no timeline to fix the IRD computer system.
Prime Minister John Key said it was an urgent problem eight months ago.
- Kate Shuttleworth of APNZ