Frank Field said he had been "dazed" by the letter from Sir Thomas
Ex-minister Frank Field says he will challenge the methods used by the independent auditor of MPs' expenses, who has demanded he pay back £7,000.
On his blog, the Labour MP complained about the "arbitrary decision" by former civil servant Sir Thomas Legg to impose retrospective expenses limits.
The MP for Birkenhead said he hoped Sir Thomas "withdraws his suggestion, but I am not holding my breath".
Many MPs are expected to write to Sir Thomas challenging repayment requests.
Previously, Mr Field had been largely unscathed by the expenses scandal, having consistently claimed less than the maximum allowance.
But he said Sir Thomas's "retrospective and unprecedented" changes to the rules had transformed his reputation from that of "honourable member to rogue".
The MP added: "Imagine that you have been driving, perfectly legally, through a 30 mile an hour zone at a speed of 25 mph.
"Imagine then your reaction when, five years later, you receive multiple fines as a decision has been taken to change, retrospectively, the speed limit to 20.
"Last week I replied to Sir Thomas. I was dazed that, as someone who has always been open about my expenses, his arbitrary decision should link me with the abuses known all too well to voters."
Mr Field does admit that over the five-year period he claimed twice for three bills amounting to £117.
He said: "The bills shouldn't have been presented twice nor paid. I regret this and have paid the money back."
Mr Field said he shared the electorate's anger about how some MPs had played the system, but insisted that what Sir Thomas had done was "simply to move around some of the characters in the honourable members' and villains' galleries".
He said: "Nowhere has Sir Thomas explained why he has changed the rules which have resulted in his recalculations."
'Frank is a saint'
Shadow culture minister Ed Vaizey, who said he had been asked to repay £266, told Sky News: "It is interesting that someone like Frank Field, who is probably regarded by the public as the most saintly MP in the Commons, has been asked to pay back £7,000 despite publishing all of his expenses for the last four or five years.
"Frank is a saint. He is complaining... but if Frank resisted it wouldn't do him any good at all."
Labour's Diane Abbott, who as an inner-London MP cannot claim second home allowance, said MPs were "furious" about the review but warned against attempts to contest the findings.
Downing Street asked Sir Thomas to review all MPs' claims made under the controversial second homes allowance since 2004, after the expenses scandal broke in May.
A number of MPs, including the prime minister and several cabinet ministers, have been asked to repay the difference between what they claimed under the rules in place at the time, and what he thinks they should have claimed.
Sir Thomas cannot force MPs to repay any money.
His final recommendations will go to the Commons Members Estimate Committee, which will then decide what to do next. The committee is due to publish its report on 4 November.
Prime Minister Gordon Brown, who has himself been asked to repay more than £12,000 by Sir Thomas, has urged his MPs to pay up and allow the Commons to move on from the old discredited system.
Conservative leader David Cameron has said that if his MPs do not pay back money at the end of the expenses review they will not be able to stand again for the party.
Lib Dem leader Nick Clegg has said that he expected all of his MPs to "co-operate fully".