The Commonwealth Ombudsman Colin Neave will investigate the government's controversial data matching-driven welfare debt collection system aimed at recouping as much as $4 billion in false payments.
Mr Porter has defended the system, saying he did not think it was unfair or unreasonable.
"We have a responsibility to the taxpayer to make sure that welfare recipients are not overpaid. Where there is information which is available to us as a government, which suggests that the earnings reported to Centrelink are different to the earnings reported by the employer to the ATO, we have a responsibility to check and to seek further information," he said.
The Ombudsman's office said Mr Neave had started to look into the complaints.