Centrelink is taking "revenge" on critics of its controversial debt collection activities by publicly releasing their private information, according to the federal opposition.
The welfare agency's parent department, Human Services, says it has the right to make public the information when it needs to "correct the record" on inaccurate claims.
But Labor Human Services spokeswoman Linda Burney reacted angrily to the disclosure.
"These are deeply unethical actions by the Government," she said.
"The disclosure has occurred deliberately to smear a private individual who has spoken out about the error prone robo-debt program and the deeply flawed Centrelink debt recovery process.
"It is unacceptable for the Turnbull Government to target individual citizens with information leaks in retaliation for their decision to speak out.
"Information held by the Department of Human Services is often sensitive and is provided with the understanding that it is confidential."
Ms Burney said Centrelink was trying to smear Ms Fox in revenge for her public criticism.
"Correcting the record is one thing, attempting to smear and discredit opponents is entirely different and far more troubling," the Labor frontbencher said.