Liberal senator Eric Abetz insists problems with Centrelink's controversial debt recovery system have been resolved.

Senator Abetz was one of four Liberal Tasmanian senators who wrote to Human Services Minister Alan Tudge calling for a solution to the problem.

He said a member of his own family was among those who claim to have received letters from Centrelink incorrectly claiming they owe money.

The matter had since been resolved by a "friendly" Centrelink staff member, he said.

"The letters now are a lot more user-friendly and invite people to consider whether the information is correct or not, rather than asserting the information is correct," Senator Abetz told ABC radio on Friday.

The government insists the system is working, rejecting repeated calls for it to halt the system until problems are resolved.

Meanwhile, the Department of Human Services is seeking private contractors to provide "advanced customer aggression training services" for its customer service staff.

The Australian Council of Social Service insists the complaints are still rolling in, accusing the government of ignoring deep levels of distress.

Labor has also called for the system to be suspended and will push for a Senate inquiry when parliament resumes on February 7.