Labor frontbencher Katy Gallagher is considering referring senior public servants to the privileges committee after receiving "misleading" evidence relating to disability employment services.
The evidence relates to a contract with Boston Consulting Group to conduct research on disability employment services and people with a partial capacity to work.
Having raised the matter at three previous Senate estimate hearings initially because of concerns the research should have been done by the department itself, Senator Gallagher questioned the accuracy of evidence she'd been given as an explanation.
She said she was given an incorrect reason for the contract increasing from $1.76 million to around $3.3 million, and was told there had been no report conducted into the matter when in fact there had been.
Senator Gallagher said she was minded to refer the matter to the privileges committee.
"I'm very concerned about the accuracy of the answers the committee has received verbally and in writing ... it does look to me from witnesses' evidence ... the committee has been misled a number of times," she said.
"I can't actually understand why considering the matter involved. But it's clear that officers of your department weren't up front with what was going on."
Social Services department secretary Ray Griggs confirmed he was investigating whether Commonwealth procurement rules had been breached.
Mr Griggs wrote to the committee stating he'd found non-compliance with internal process and some "less than better" practice regarding the procurement rules.
"It's clear it wasn't well handled," he said.
He said he was waiting for evidence from key decision-makers before finalising his investigation.
Social Services minister Anne Ruston said she was "absolutely sure" officials had not deliberately misled the committee.
