Ian Paisley Jnr has stonewalled further questions about his expenses claims after it was discovered he received a £4,000 advance.
It comes after Mr Paisley was revealed as claiming more expenses than any of the 650 other MPs during the 2012/2013 House of Commons term.
He topped the board with a combined cost totalling £232.042.33 to April 2013.
But, following the most recent revelation, Mr Paisley refused to comment as to why or when he received the substantial advance.
He referred the Belfast Telegraph to his previous statement in which he termed the expenditures, including £28,761.36 for office cost allowances such as electricity bills, stationary, newspapers and rent, as "unavoidable costs".
He said: "The business expenses are unavoidable costs that an MP incurs whilst running a busy constituency office and commuting to Parliament.
"I am doing a full-time job with one of the highest speaking records in the Parliament. I also ask an above average number of questions to the Government."
Out of the total amount, £131,837.76 goes on a payroll for his four full-time and two part-time staff while a further £69,946.21 went on parliamentary expenses.
The North Antrim MP's expenses included £24,904.13 on accommodation and £45,039.08 on travel and other expenses. He said: "I host a significant number of constituent visits to Parliment even during recess and my constituency has benefited in terms of coverage, jobs and investment."
"Once again, I stress, none of this money goes to me as MP or my family. They are legitimate expenses signed off by IPSA."
Eleanor McGrath from the Tax Payers' Alliance said that while politicians should get appropriate support for their work, taxpayers have every right to question the amount of money they claim.
The news comes after the shock resignation of SDLP MLA Conall McDevitt after it was discovered he failed to declare £6,000 earned from a public relations company.