Mac Harb is stepping down from the Senate, dropping his legal action and repaying tens of thousands of dollars more because of inappropriate living and travel expense claims, CBC News has learned.


Harb, who was a Liberal senator until his spending came under scrutiny through an external audit, has already paid back $51,482.90. He did so under protest and had asked the court for a judicial review of the order from the Senate to pay money back.


His lawyer is expected to issue a news release announcing Harb's retirement.


Speaking to CBC News, Harb said he "is relieved after 28 years in public service to become a private citizen. The last couple of months have been very hard," he told the CBC's Hannah Thibedeau, adding that he is relieved to move forward.


Harb, who was the MP for Ottawa Centre for 15 years until he was appointed to the Senate in 2003, maxed out on his parliamentary pension in 2007.


In May, the Senate internal economy committee said Harb owed $51,000 in expenses claimed over the past two years. In June, Harb was sent a letter ordering him to pay that amount.


The Senate also advised Harb to repay more than $231,000 claimed since 2005 or face an extensive audit of his expense claims over that period.


His expenses were controversial because of his claim that a home near Pembroke, Ont., is his primary residence. Senators whose primary residence is at least 100 kilometres from Ottawa are permitted to charge living and travel expenses.


The RCMP is looking into the audit that was done on Harb's expenses and in court documents filed earlier this summer, an investigator said he believes the senator really lives in Ottawa and should not have claimed the housing and travel expenses over the years.