Three new privacy breaches involving Work and Income New Zealand have emerged, but Social Development Minister Paula Bennett says there is not a systemic problem with privacy at the government department.
One case occurred in Masterton when a confidential document containing a client's details was used as scrap paper and given to another client.
In a second case a Wanganui man told APNZ he went to Winz for a work seminar and was given a folder with job listings. He said it contained a document with another client's personal information.
In a third incident, Whitirea journalism student Jean Eltringham was given another client's details in a pile of papers during a meeting at a Kapiti Winz office in August.
Speaking about the Masterton incident, Ms Bennett said Winz offices had procedures to dispose of personal documents in locked bins but they were not followed.
"The incident that has come to light today is someone who made a mistake - they are always disappointing as mistakes are, but one can't always mitigate against human error," she said.
Prime Minister John Key called the breach unacceptable but said it was the sort of thing that could happen to any person working in a company.
"I think we've got to give the people who work at MSD a bit of credit - they try very hard, they do a good job and time-to-time people can make a human mistake, I think we've got to cut people a little bit of slack," he said.
Ms Bennett said the breach did not constitute a systemic failure and said it was a one-off incident.
She confirmed she had been briefed about the two other incidents.
Head of Work and Income Debbie Power said the Masterton incident would be addressed with staff and appropriate action taken.
The clients involved were being contacted. The Privacy Commissioner's office confirmed it received notification of the breach.
The latest blunders come after the Ministry of Social Development closed self-service kiosks at Winz offices across New Zealand after blogger Keith Ng revealed he was able to access thousands of private files on ministry servers.
An independent inquiry will look at how that breach occurred and what could be done to prevent another.
Labour's social development spokeswoman Jacinda Ardern said there had been 10 reported incidents this year involving information leaks.
She called for the investigation to be broadened to include the recent client privacy breaches but Ms Bennett said it would not.