Arlene Foster and Martin McGuinness have hit back at an attack by Jim Allister on their average monthly £45,000 bill for trips and hospitality.
The First Minister and Deputy First Minister insisted they would "leave no stone unturned" in their drive to promote Northern Ireland and win new jobs.
And in a jibe at the TUV leader, they said they would leave it to others to "pull down the shutters".
Questions by Mr Allister unearthed that the newly-titled Executive Office spends an average £33,000 each month on travel, with a monthly total on hospitality of a further £12,000.
The total spend on travel and hospitality for 2015/16 was £396,406.
On hospitality, the total between June last year and this May was £144,066. The biggest spend was £29,000 in March and the lowest was less than £5,000 last August.
"Put together, almost £50,000 per month of taxpayers' money is going on travel and hospitality for OFMDFM," said Mr Allister.
"Of course some level of expenditure is necessary, especially in running the foreign offices, but an overall level of over £540,000 per annum for one department does seem extravagant." A statement on behalf of Mrs Foster and Mr McGuinness said: "Over the last five years Invest NI has secured 87 new investors for Northern Ireland.
"These investors will create 4,327 new jobs and generate £255.6m investment into our local economy.
"Ministerial visit programmes are a vital part of Invest NI's Foreign Direct Investment strategy, with investors often citing access to our government as a unique strength.
"While others may prefer to pull down the shutters, we intend to continue to leave no stone unturned to promote Northern Ireland as a great place to live, visit, work and invest."