Speaker Trevor Mallard and National Shadow Leader of the House Gerry Brownlee would not "run over to Japan for a junket if they don't have to", says Labour MP Kieran McAnulty.
The pair have copped criticism after flying to Tokyo over the weekend to watch the All Blacks Test match in a trip they described as "sports diplomacy". It was estimated to cost taxpayers $24,000.
Mr Mallard has defended the trip, saying with the Labour Party conference on, there was a lack of ministers available to go.
On TVNZ1's Breakfast this morning, National MP Denise Lee said it was an important trip for trade.
"We're a small nation, a trading nation, we've got to keep up relationships, you can't just do that over emails. Face-to-face meetings are really important and my understanding is that they had a jam-packed programme.
"Yes, it included the rugby but they really worked hard, in fact so hard in the nature of the programme caused Gerry Brownlee to say he wondered why there wasn't a Labour Party Cabinet Minister on the trip with them."
Labour MP Mr McAnulty said "we've got to take those blokes' word on it".
"They're experienced politicians. If they'd have stayed a week then people may find that to be more of a legitimate time spent, but then that would probably be five times the cost.
"They're both old men, they're not going to run over to Japan for a junket if they don't have to."