Centrelink is under fire for letters using the AFP's logo and language that critics say is intended to intimidate clients into updating their personal details.

The agency has sent out the letters within months of prolonged controversy over the wording of notices it sent to welfare recipients about possible "robo-debts", and after Department of Human Services officials were forced to defend them.

Centrelink is under fire for letters using the AFP logo. Credit:Erin Jonasson

Letters sent to welfare recipients in late July have an AFP logo beneath Centrelink's and tell them to keep their personal details up to date, before listing a series of penalties if they commit welfare fraud, including a prison sentence and a criminal record.

"The majority of our customers do the right thing and tell us about any changes to their information. We also know that sometimes people make honest mistakes, however customers who deliberately withhold or provide false or misleading information could be committing fraud," it said.