The scam is being probed by the Home Affairs department, secretary Mike Pezzullo confirmed to a Senate estimates hearing on Monday.

Mr Pezzullo said Mr Maguire had made representations to the department as well as federal MPs.

"I believe that to be the case and I've asked for further particulars to be established in that regard," he said.

Mr Pezzullo was unable to say who the disgraced MP had approached, but a full report was being prepared by Home Affairs.

The law would be applied "without fear or favour", he said.

The cash for visas scheme dates back to 2013 and came to light during a NSW Independent Commission Against Corruption inquiry into Mr Maguire's alleged abuse of his public office while a state MP between 1999 and 2018.

Mr Pezzullo said other people linked to the scheme had previously come to the attention of Home Affairs and Mr Maguire's name had come up in department records.

The Home Affairs boss said the department was focused on helping the NSW ICAC while running its own probe.

"We'll work in parallel with ICAC, we'll work in a way that we won't cut across them," Mr Pezzullo said.

Mr Maguire once received deliveries of thousands of dollars of cash to his tax-payer funded office.

The money was associated with a scheme that involved securing Australian visas for Chinese nationals.

Australian Associated Press