Pressure is mounting for an independent review of MPs' travel entitlements after the resignation of former Cabinet minister Pansy Wong following revelations her husband conducted business while on taxpayer-funded trips.
Mrs Wong resigned from her women's affairs and ethnic affairs portfolios on Friday after admitting her husband, Sammy Wong, conducted business while on a trip to China in late 2008.
Mrs Wong and Prime Minister John Key have indicated there may be other incidents of misuse and Speaker Lockwood Smith is reviewing Mrs Wong's travel expenses.
MPs are entitled to pay for personal travel with their spouses but rules clearly state it does not apply to trips related to personal business.
The incident is the latest in a long line of abuses of the travel perk.
Although not breaking the rules, perk-buster and ACT Party leader Rodney Hide repaid money after it was revealed he used the entitlement to take his partner on an expensive overseas trip.
Mr Key said there may need to be changes to the travel entitlement but he would need to get advice on the matter.
"It's not so much getting rid of it, the question is would there be any salary adjustment," he told media at an Asia Pacific Economic Co-operation forum meeting in Japan yesterday.
The entitlement was a relic of the past, he said.
Green Party co-leader Metiria Turei said Mrs Wong's resignation was further proof of the need for an overhaul of MPs' travel entitlements.
Paying MPs through international travel subsidies caused confusion and perverse incentives, she said.
"John Key needs to establish an independent body to develop a more transparent system that clearly separates personal expenses from remuneration and legitimate work expenses."
An independent review would keep MPs honest and transparent, Ms Turei said.