Senator Pamela Wallin called an independent audit of her expenses "fundamentally flawed and unfair," but said she will repay any disallowed claims with interest because she wants to move on.

The audit, which will be made public Tuesday, is expected to put a renewed focus on questions about the role senators should play when they are appointed to the Red Chamber. Ms. Wallin said Monday that she entered the job determined to be an "activist senator," a position she said requires frequent travel to public events and speaking opportunities.

Ms. Wallin told reporters Monday afternoon that she believes auditors used an arbitrary definition of what constitutes "Senate business" in determining that some expenses related to her public appearances and speeches should not have been claimed.

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"When invited to appear publicly and speak on subjects including the role of women in public life, Canada's mission in Afghanistan, and support for our troops, I saw it as my duty to accept whenever able to do so," she said.

"Travel to these public speeches and appearances was, and is, in my continuing view, a legitimate Senate expense," Ms. Wallin said.

Auditors uncovered more than $121,000 in improper claims made by Ms. Wallin since her appointment to the Senate in January, 2009, according to a source familiar with its contents. They also flagged another nearly $21,000 that will be subject to further review by the Senate internal economy committee to determine if it was justified, the source said.

The audit also indicates that Ms. Wallin altered her Outlook calendar around the time she began to face pressure over her spending habits to suggest that her travel was for a different purpose, the source said. Ms. Wallin said Monday that she made "no attempt" to mislead the auditors but made the changes because she was advised during the course of the audit to include only information that was relevant to the expenses being claimed.

"So we formatted our calendar accordingly and added as much additional information as we had regarding the claims, without irrelevant, private or personal information included," Ms. Wallin said in her statement. "We knew that Deloitte had a copy of the original calendars available to them at all times."

In total, auditors found 83 additions, 34 modifications and 391 deletions to entries in Ms. Wallin's electronic calendar, the source said. As an example, auditors highlighted a trip Ms. Wallin made to Saskatoon in mid-June 2009. The original electronic calendar entry that the trip was for "Saskatoon event (4 riding fundraiser)," but that was altered after December, 2012, to remove any mention of the riding fundraiser, according to the source.

In a separate event, Ms. Wallin changed her Outlook account to say that she was in Guelph, Ont., on a particular date to meet with an official from the World Bank and another official from New York. Auditors questioned her version of events, noting that Ms. Wallin was known to have attended a convocation ceremony at the University of Guelph that morning in her role as chancellor.

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The former broadcaster, who was appointed by Prime Minister Stephen Harper but now sits as an independent, has so far paid back $38,000 to the Senate. Ms. Wallin admitted in a CBC interview earlier this year that she "made mistakes" on some of her claims related to her work on corporate boards.

Ms. Wallin previously held paid positions on the board of Porter Airlines and Gluskin Sheff + Associates Inc., a Toronto-based wealth management firm, but resigned from both earlier this year.

Other expenses highlighted by the auditors include personal trips Ms. Wallin made between Ottawa and Toronto and stopovers in Toronto while she was en route to Saskatchewan. She has previously stated that she often stayed in Toronto on her way home because there are a limited number of direct flights to Saskatchewan.

"I never intended to seek, nor sought reimbursement for travel expenses in any situation where I did not believe such a claim was proper," Ms. Wallin said Monday. "Where I made mistakes, I have already paid money back."

Ms. Wallin suggested that the Senate's current travel policy, which was last revised in June, 2012, was applied retroactively to the review of her spending. The policy indicates that travel to participate in community festivals or speaking engagements related to a senator's work is considered a legitimate Senate expense, while travel that is focused on topics "of personal interest to the senator" and participation in charity and volunteer work must be paid from a senator's personal funds.

The committee was expected to debate whether or not to refer the results of the audit to the RCMP, another source familiar with the committee's work said on Monday afternoon. The RCMP is investigating expense claims by senators Mike Duffy, Patrick Brazeau and Mac Harb – three other senators whose expenses were audited earlier this year. An RCMP spokeswoman said Monday that the force is not in a position to comment on anything related to the Senate.

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Conservative Senator Marjory LeBreton, the leader of the government in the Senate, issued a statement Monday afternoon saying the government "will not tolerate the waste or abuse" of taxpayers' money and expects that inappropriate expenses will be repaid.