Senator Pamela Wallin must repay up to another $100,600 in expense claims by Sept. 16 or could see her wages garnisheed, Senate officials say.

Ms. Wallin was given 30 days to repay her claims after a letter was hand-delivered on Aug. 16, three days after the audit into her expenses was publicly released.

Auditors had found $121,348 in expenses they said should be repaid, and asked the Senate for an "interpretation" on another $20,978. On Aug. 21, a Senate sub-committee said $17,621 of that figure must be paid back, for a total of $138,969.

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Given the final figure was determined after the letter was delivered, it's unclear what sum Ms. Wallin must repay by the Sept. 16 deadline. It would be at least $82,979, but the Senate is ultimately seeking another $100,600 from her.

Ms. Wallin had already repaid $38,369 at the time of the audit's release. Senate officials said this week she hasn't repaid anything else since, and her lawyer declined to comment on repayment. Ms. Wallin dismissed the Senate process as "flawed and unfair" in a statement the evening before the audit's release.

The Senate will take the money by garnishing her wages if it doesn't receive payment by the end of the day on Monday, Sept. 16, Senate spokesperson Brigitte Lemay said in an e-mail Thursday.

The Senate resorted to garnishing the wages of Senator Patrick Brazeau, who was ordered in a letter sent May 28 to repay $48,745.13. He was given 30 days but didn't pay in time.

Two other senators' expenses were audited and referred to the RCMP: those of Mac Harb, who has since retired, and Mike Duffy. Both repaid the money the Senate was seeking.

Mr. Brazeau, Mr. Duffy and Ms. Wallin continue to serve as senators.

The Auditor-General is now preparing to review the claims of all senators, a process that's expected to take 18 months.