OTTAWA - Sen. Carolyn Stewart Olsen, a longtime Stephen Harper confidante, is stepping down from the Senate committee that sat in judgment on colleagues embroiled in the expenses scandal.

Her reasons for leaving were not immediately clear, but she has told other senators she needs a break from her hectic schedule.

However, Stewart Olsen herself was recently accused of wrongly claiming more than $4,000 in accommodation and meal expenses at a time when she was not involved in any Senate business.

She has denied the allegation but the chair of the internal economy committee, Sen. Gerald Comeau, has asked Senate finance officials to review Stewart Olsen's expenses and refer any irregularities to the auditor general, if necessary.

On Tuesday, Sen. Mike Duffy implicated Stewart Olsen in the ultimatum he says he was given by the Prime Minister's Office -- that if he didn't pay back his disallowed $90,000 in expenses, she and fellow committee member Sen. David Tkachuk would declare him unqualified to sit in the Senate.

Stewart Olsen and Tkachuk have also been accused of whitewashing the initial committee report on Duffy to essentially exonerate him of any deliberate wrongdoing.