Work and Income cancelled Graham Wills' sickness benefit after misplacing his medical forms, which were later returned to him by another beneficiary.

Social Development Minister Paula Bennett is refusing to expand an existing inquiry into the security of the Social Development Ministry's information technology systems, despite several revelations about privacy breaches.

Mr Wills, now 65, has since become eligible for government superannuation payments but he said he was appalled when his private medical information was mistakenly sent to another client last year.

The Wellington, resident contacted Work and Income after his benefit was cancelled. He was told it was because he had not provided updated medical information.

He had taken the forms into the local Work and Income office and asked for a receipt.

"I always walk them in because Work and Income's biggest excuse is, ‘Oh, it's lost in the mail'."

The Work and Income officer said the forms must be somewhere in the office and asked him to fill them out again, he said.

Several days later, Mr Wills found the original forms in his letterbox.

A fellow beneficiary had "very sweetly" returned them with a note signed only "J" - "a wee note saying, ‘These were amongst my documents sent to me"'.

"My instant reaction was, ‘What's this? This is not mine'. Then I realised it was," he said.

In his three years on the sickness benefit, the behaviour of Work and Income had added to his stress and anxiety.

He did not contact Work and Income after he received the original forms because he had "had enough".

"The gall of that minister to stand there and say, ‘It's an isolated case, it's a one-off'. Give me a break. It seems to me from what I read and from what I hear on the grapevine that it's endemic throughout the whole organisation."

Labour social development spokeswoman Jacinda Ardern said the Government must broaden the inquiry into the ministry's information systems.

She said she had heard from a woman in a small town who was sent the private information of another woman after asking for a printout of her own benefit details.

"It is nonsense for Mrs Bennett to claim these are isolated cases of human error when there are clearly systemic issues at play," Ms Ardern said.

Work and Income head Debbie Power said Work and Income staff had talked to Mr Wills about 15 times in the past year and as far as they were aware, he had never raised the matter with them.

- © Fairfax NZ News