STAFF disciplinary action may be considered after a review of how Centrelink wrongly told 63,000 single parents to destroy their concession cards.
Fairfax Media revealed on Monday that Centrelink would contact single parents to explain they did not need to stop using their discount cards after moving to Newstart dole payments.
From January 1, people whose youngest child had turned eight were no longer eligible for single parenting payments and moved on to the lower Newstart allowance.
The Department of Human Services said the computer-generated letter ''pulled together a number of paragraphs depending on the individual person's circumstances''.
''The incorrect paragraph on concession cards was included in error,'' a spokeswoman said.
Asked whether anyone would be disciplined over the matter, the spokeswoman said departmental secretary Kathryn Campbell was investigating.
''The issue is currently being reviewed, and following this review the secretary will consider what needs to occur,'' she said.
The department said its priority was to ensure affected parents understood their entitlements and would write to recipients to apologise.
Newstart recipients who were principal carers for their family would remain entitled to the pensioner concession card.
New cards would be mailed by the end of this month.
The federal opposition argued the incident showed ''the left hand of this government doesn't know what the right hand is doing''.
The December letter, headlined Cancellation of Your Parenting Payment, explained that federal government changes meant the allowance was being cut if the youngest child was at least eight years old.
It said the pensioner concession card was valid only until the end of December 2012 and recipients should ''destroy this card immediately after this date''.
The message warned that organisations providing concessions could check electronically with Centrelink to ensure cards were not misused.
In 2006, the former Howard government began the process of moving single parent payment recipients on to Newstart but ensured those who were already receiving the payments could continue to do so until their youngest child turned 16.
The move to Newstart will mean the maximum support drops by $65 to about $267 a week.
Newstart also has stricter rules about how much additional income a person can earn before the allowance is reduced.