Social Services Minister Christian Porter says there have only been 276 complaints out of 169,000 Centrelink debt letters.
The social services minister has defended Centrelink's "polite" debt letters generated by a new automated system amid criticism some welfare recipients have been hounded over false debts.
Christian Porter confirmed so far this financial year 169,000 review letters have been sent out, indicating there might be discrepancies after data from different agencies is matched up.
"The complaint rate is running at 0.16 per cent... only 276 complaints out of 169,000 letters and that process has raised $300 million worth of money back to the taxpayer," he told ABC Radio on Tuesday.
The federal government is looking to claw back $4 billion in overpayments.
Mr Porter characterised the letters as polite.
He declined to provide the number of people who are challenging the debt letters.
Mr Porter said the letter asks people to provide more information which they can do online.
He dismissed claims there were problems with the Centrelink website.
"If anyone is having difficulties they can seek an extension of time if they wish," he said.
Mr Porter said the high volume system was "working incredibly well".
Welfare recipients are tweeting criticism of the system under the hashtag #notmydebt.
Labor's spokeswoman on human services Linda Burney has called for the system to be suspended.
"Get it right before threatening people - not that hard," Ms Burney tweeted.
She said no MPs who checked the emails to their electorate office could possibly say the system was working.