ACT leader Rodney Hide says he disagrees with the perk that gives MPs a taxpayer-funded 90 percent fare discount for themselves and their partners - but he still used it to take his girlfriend overseas.
The air fares for Louise Crome's trip to London, Canada and the United States are reported to have cost $25,163.
Mr Hide's fares and accommodation cost $26,872.
He said today the perk was "a silly anachronism" but it existed and he couldn't change it.
"I don't agree with that rule but I'm not a martyr," he said on Radio New Zealand.
"I checked twice with the prime minister that it was acceptable. It got all the ticks."
Mr Hide made a name for himself as a "perk-buster" when he first came to Parliament and demanded an end to allowances such as the one he used to take Ms Crome overseas.
He is minister of local government and took the trip to see for himself how other cities handled changes to their council structures.
Prime Minister John Key has told ministers they should pay for their partners themselves if they want to take them on official trips, but that didn't apply because Mr Hide used the concession that all MPs get.
"I made a decision to go on this trip because I've got a very big job in Auckland implementing the transition," he said.
"I then had to justify whether or not I took my partner. I think it's important for me personally, but more particularly for me to do a good job as an MP and a minister, that I maintain my private and personal life."
Mr Hide said he was away from home most nights and days.
"We get very little opportunities to get time together."
MPs' travel claims have been revealed in the latest disclosure of their expenses, released yesterday.
TV One News reported tonight Mr Hide wasn't the only minister taking advantage of the 90 percent discount for MPs.
Agriculture Minister David Carter spent nearly $12,000 taking his wife overseas and on domestic travel while Housing Minister Phil Heatley spent a similar amount, including $1000 for his wife to holiday with him in the Cook Islands.
Environment Minister Nick Smith spent $13,000 but only for travel in New Zealand while Labour MP Ross Robertson took his wife to Sweden.
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