"I'm very sorry obviously that I've caused all of this grief for family and my friends and for my fellow parliamentarians, and I think taxpayers have a right to know," she told Mansbridge.
Auditors are currently going over Wallin's travel expense claims going back to January 2009, when she was first appointed to the Senate. It has been reported that Wallin has claimed about $350,000 in travel expenses since September 2010.
Wallin said she made mistakes on her claims for flights.
"I sign the documents, so I take responsibility," the former journalist and diplomat said. "I take full responsibility for this. I should have gone over it with a fine-tooth comb as anybody should and make sure, but I just didn't."