David Laws resigned as Chief Treasury Secretary on Saturday and will be replaced by fellow Liberal Democrat Danny Alexander.
Laws apologized Friday for channeling the funds to his long-term partner, James Lundie. He said he would immediately pay back the money, which the Daily Telegraph newspaper said totaled 40,000 pounds ($57,822).
Parliamentary rules banned lawmakers from leasing accommodation from spouses, family members or a "partner" since 2006.
Prime Minister David Cameron has promised to crack down on politicians' abuse of expenses.