Former Cabinet minister Sir Douglas Graham says he would give up his international travel subsidy in exchange for a pension increase - but only when he is too old to fly.

"I worked extremely hard down there [in Parliament]. This [the subsidy] was part of the deal, and as long as I can use it I will use it."

Sir Douglas said yesterday that he "absolutely" had used his 90 per cent discount, and was leaving for Boston within the next few weeks.

"I have no qualms whatsoever. Most years we have gone somewhere."

Sir Douglas was National MP for Remuera MP from 1984 to 1999 and held several portfolios, among them Minister for Treaty Negotiations and Attorney-General.

He said he and other MPs turned down salary increases while in Government, and as a result he left Parliament with "hardly any money".

The subsidised travel was "part of the deal" when he left politics, Sir Douglas said, but he would give it up for the only acceptable substitute, "cash".

"What other form is there - food?"

Sir Douglas said he left Parliament with a pension of about $300 a week.

During further discussion about keeping his subsidised travel, he said: "You better keep paying your taxes".

Green Party co-leader Metiria Turei will seek an independent review of the travel subsidy when the Parliamentary Service Commission meets this month.

Act leader Rodney Hide added his voice to Ms Turei's, saying he was responsible for eliminating the perk for MPs entering Parliament after 1999, but he had never been able to gain support for cancelling it for former members.

His Act colleague Sir Roger Douglas used his 90 per cent discount to fly himself and his wife to Britain to visit family, but Mr Hide scoffed at claims from former MPs that it should remain.

"If you're an ex-MP and you've got the perk, of course you'd love it. But it was another time in New Zealand.

"It's hard to believe we ever did that, but that's how things used to operate. There were always perks in doing jobs and now there aren't perks.

"That goes right across New Zealand, and Parliament should be the same," Mr Hide said.

Claims the travel subsidy was part of the employment package at the time and compensation for accepting lower salaries were rubbish, he said.

It was bestowed by the Cabinet, rather than an independent commission, and its real value had never been known or taken into account.

The perk seems to be well used.

Judith Tizard, former Labour MP for Panmure and Auckland Central, hung up on the Herald yesterday, but not before confirming that she had taken a taxpayer-funded trip to the United States.

Former Tamaki MP Clem Simich has used his 90 per cent travel subsidy only once since leaving Parliament last year. He travelled to New York this year, but doubts he will be going anywhere else any time soon.

He said the former MPs claiming the subsidy "absolutely" deserved it, though it was no longer relevant.

The first time "perks" were formally taken into account in MPs' salary packages was in 2003, when the Remuneration Authority overhauled the way they were paid.

They received a boost in their base salaries from $90,500 to $110,000 to make up for losing several allowances.

But the authority estimated the full salary package at $142,700 - including $32,700 as the value of other perks, among them the travel subsidies.

Prime Minister John Key has said he will not block a review of the international travel perks, and Labour leader Phil Goff has said he would be comfortable with any review.