New Zealand First is calling on Trade Minister Tim Groser to repay what it calls his exorbitant travel costs during his unsuccessful campaign for the top job at the World Trade Organisation.
Mr Groser was on a shortlist of five for the job of director-general but failed to get enough support from the WTO's 159 member countries in the second round of voting.
Herminio Blanco (Mexico) and Roberto Azevedo (Brazil), are through to the final round of competition to succeed Pascal Lamy on 1 September.
Mr Groser spent nearly $250,000 on international travel in the first three months of this year.
New Zealand First MP Andrew Williams says it was a waste of taxpayers' money and the minister "should do the honourable thing and admit the fact that he wasn't up to the job, he couldn't get the job".
Mr Williams says, given that Mr Groser gets a minister's salary as well, he should refund a "big chunk" of his travel costs.
Why he didn't get it - former diplomat
A former top diplomat says Mr Groser missed out on the job because developing countries want more of a say in the WTO.
Terence O'Brien, a former New Zealand ambassador to the United Nations who is now a senior fellow in strategic studies at Victoria University, says Mr Groser didn't get the job because Westerners have held it for too long.
"They've had over half a century's worth of control," he says, "and large developing countries whose economies are now vital to the success of the world economy feel it's about time they had an equivalent opportunity."
Mr O'Brien says it was doubly difficult for Mr Groser because a New Zealander has already held the job of WTO director-general: former prime minister Mike Moore between 1999 and 2002.