Former international development secretary Clare Short wrongly claimed more than £8,000 in parliamentary expenses, according to reports.
In the latest newspaper disclosure, Ms Short was said to have claimed the full cost of her mortgage for two and a half years despite being entitled to charge only for the interest.
Ms Short, who now sits as an independent MP after having quit Tony Blair's Cabinet over the Iraq War, paid back the money after the error was pointed out by the Commons Fees Office in 2006.
A report said Ms Short only agreed to pay back the sum of £8,436.36 after complaining that the Fees Office had not spotted the mistake earlier.
In a letter to the Fess Office, Ms Short wrote: "I, of course, accept that I should make a repayment but I think your office should accept some responsibility for this situation.
"I was not clear about the rules on capital and interest and always sent in documentation and am surprised your office did not pick up the problem."
Ms Short said: "When I found out that I had been making a mistake, I was embarrassed and irritated that it took the Fees Office so long to pick this up.
"I paid what was due and corrected future claims. I think this is an example of the Fees Office working as it should, if a little belatedly."
The report said Ms Short, the MP for Birmingham Ladywood, had claimed hundreds of pounds worth of work to a summer house and conservatory, as well as her porch, patio and kitchen at her second home in Birmingham.
She also charged more than £1,500 for repainting.
The records also appeared to suggest Ms Short had submitted twice an identical £599.14 for decorating and renovation work and was paid twice.
She added: "I will have to ask the Fees Office about this. I cannot understand it. It would surely be impossible to submit the same bill twice.
"I have written to the Fees Office to ask them to check. I will refund any money if it is due."
Ms Short said it was an "honest mistake" when she switched from an interest-only to a repayment mortgage after she left the Government in 2003.
She said: "This is years ago. So the system worked. I made a mistake, the money was repaid, there is no fiddle of any kind, no milking the system."
She added that she had only claimed for the "basic maintenance" of her house in Birmingham.
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