Act MP and "Perk-buster" Rodney Hide has repaid the $10,000 cost for a tax-payer funded private holiday he took with his girlfriend in Hawaii.

The Act leader, already under scrutiny after taking Louise Crome on a ministerial trip to Europe and America in September, also took her on a holiday to Hawaii in July, the Weekend Herald reported.

Mr Hide repaid the money without publicly revealing anything about the holiday this week.

A spokeswoman for Mr Hide told the newspaper Ms Crome had gone to Hawaii using the "holidays perk" - a 90 per cent subsidy MPs and their partners get on private international travel.

"He booked the flights through parliamentary travel but after reflecting on that decision over the last week or so, he decided to repay the full cost of the Hawaiian airfares."

He had repaid the $10,022.40 cost of the flights this week.

Ms Crome's flights to Europe and America cost about $12,000, on top of the $26,872 for Mr Hide's ministerial travel.

Mr Hide has been heavily criticised for using the perk to take Ms Crome with him.

Using the MPs perk allowed Mr Hide to get around a directive by Prime Minister John Key that ministers wanting to take partners on international travel should pay for it themselves.

- NZPA