Ian Paisley had his official credit card suspended after running up almost £6,500 in expenses debts, it can be revealed.
The North Antrim MP was one of 19 Commons members who have had their payment cards temporarily suspended by the Independent Parliamentary Standards Authority (Ipsa) since January 1 this year.
It can also be revealed that Mr Paisley owed £13,833.38 on June 29. A spokesman for Mr Paisley said the matter had been addressed earlier this week.
The MPs were subject to action by the Commons watchdog after failing to show spending was valid. The details were disclosed in response to a Freedom of Information (FoI) request by the Press Association. The Independent Parliamentary Standards Authority (Ipsa) issues MPs with credit cards to pay for items such as travel and accommodation.
The politicians then have to prove the spending was genuine by the end of the month, or they build up debts to the watchdog.
According to the FoI response, Ipsa has suspended the cards of 19 MPs since the beginning of this year because they have not settled outstanding sums.
The debts were then recouped by not paying out valid claims filed by the politicians.
However, former East Belfast MP Naomi Long has criticised the system as a "shambles".
"It took me five phone calls and two days to log in in May/June to do the online reconciliation which may explain why there are issues with MPs being late with submissions," she revealed.
"I then sent all my receipts to Ipsa weeks ago - they claim never to have received them and I spent another three hours trying to get replacements."
An Ipsa spokesman stressed that the debts from June 29 were a "snapshot" and could merely be awaiting evidence from MPs that they were valid claims.
"An MP may owe an amount to Ipsa for many different reasons, and the fact that an amount is owed does not, in itself, indicate any misuse of the MPs' Scheme of Business Costs and Expenses," the spokesman said. "As part of our credit management programme, MPs are sent financial statements detailing their monthly position with Ipsa. Where MPs have amounts owed to Ipsa, action is taken to recover these amounts."
A spokesman for Mr Paisley said: "This figure was a result of unreconciled invoices. The matter has been addressed this week."
Work and Pensions Secretary Ian Duncan Smith was also among the 19 to have his official credit card suspended.
Mr Duncan Smith's card was blocked when he owed £1,057.28. He does not currently have any debt.
Others to have their cards suspended included his Labour opposite number Rachel Reeves, who owed £4,033.63 at the time.
Shadow business minister Toby Perkins was subject to action when he owed £693.30.
Health minister Ben Gummer had his card stopped with £1,290.07 outstanding, defence minister Mark Lancaster had a £600 tab, and former universities minister David Willetts owed £1,172.05.
Former Labour MP Eric Joyce had his card blocked when he owed £12,919.61, and later had his salary docked. All have since cleared their debts.
Ipsa also released information about 25 MPs who had sums outstanding as of this week.
Mr Paisley owed £13,833.38 on June 29. He previously had his card blocked when his tab hit £6,195.94.
Lib Dems Stephen Gilbert and Mike Crockart had their cards stopped when they owed £2,925.76, and £720.64 respectively. Mr Gilbert owed £13.50 this week and Mr Crockart £90.