The former Conservative has until Sept. 16 to repay tens of thousands of dollars in ineligible travel expenses.
A Senate official confirmed the upper chamber will start garnishing Wallin's wages if she misses that deadline.
The Senate called in the RCMP after an audit called into question a litany of travel claims spanning nearly all of Wallin's career as a senator, which began late in 2008.
The auditors flagged $121,348 in inappropriate expenses and the Senate committee later determined Wallin owed another $17,621, bringing her total tab to $138,969.
Wallin — who denounces the audit as "fundamentally flawed and unfair" — has already repaid $38,000, and has since promised to reimburse any disallowed expenses out of her own pocket, with interest.
Wallin is one of four senators in hot water over their expenses.
The Mounties are investigating the questionable housing claims of former Conservatives Mike Duffy and Patrick Brazeau as well as ex-Liberal Mac Harb.
The Senate has begun docking Brazeau's pay, while Harb used mortgages against four of his properties to get loans from a numbered company owned by an Ottawa businessman to pay back his ineligible expenses.
Harb has since resigned from the Senate.
Prime Minister Stephen Harper's former chief of staff, Nigel Wright, cut Duffy a $90,000 cheque to pay back his housing claims.
Meanwhile, La Presse is reporting the Senate ethics officer has opened up an investigation into another member of the upper chamber, Pierre-Hugues Boisvenu.
Boisvenu has admitted to a relationship with former aide Isabelle Lapointe. She eventually left his employ to work elsewhere in the Senate.
Le Presse said the ethics officer is to investigate whether Boisvenu gave an inappropriate benefit to Lapointe.
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