She lives in New York, but former prime minister Helen Clark still claims about $20,000 a year in domestic travel from New Zealand taxpayers.

And Jim Bolger, who has not been prime minister since 1997, spent more than most of today's working MPs between 2011 and 2012, when taxpayers forked out $51,500 in travel expenses for him and his wife.

The travel allowance for former premiers allows them, or their spouses, free internal flights, cars, trains, ferries, and chauffeur transfers for the remainder of their lives.

The total cost to taxpayers is more than $100,000 on average each year. For most former prime ministers, , the benefit is on top of an annuity payment of between $19,400 and $48,500 each.

The costs have been revealed under the Official Information Act, and come a week after Government ministers' travel expenses were disclosed, showing Economic Development Minister Steven Joyce charged taxpayers $1200 for a Sydney taxi fare.

Joyce defended the $1248 taxi trip as "cost-effective", saying he used the car five times over the course of a day while he was in Sydney for the Australian Jobs Fair Series last November.

Now the latest revelations show some former leaders are claiming more than current MPs, based on the quarterly travel expenses released on Friday.

Thirteen members of Parliament are on track this year to spend less than Bolger, who clocked up $24,391 of national travel for himself and wife Joan from July 2013 to June 2014.

The previous year he spent $35,179 – more than the national median income. In comparison, the lowest-spending minister, Peter Dunne, looked to have a bill of about $31,000 this year, based on the quarterly figures.

Bolger spent the highest amount of all former prime ministers and spouses in the past three years, at $111,000. The lowest was $11,541 spent by Sir Bill Rowling's widow, Glen.

Current Prime Minister John Key and all his predecessors will receive unrestricted free travel for life. However, an amendment last year means his successors and their spouses will be able to claim public money for travel only to fulfil their commitments as former prime ministers.

The Law Commission recommended in 2010 the unrestricted entitlement be reviewed in light of "current trends towards greater restraint and accountability in the use of public money".

MPs had their unlimited domestic travel benefits cut for all those who joined parliament after 1999.Bolger's expenses, like those of Dame Jenny Shipley, have declined steadily over the last three years. But Bolger said he had not aimed to make any cutbacks.

"I only use it when it's appropriate. Maybe there were less events, who can say."

Clark's husband, Peter Davis, who lives and works in Auckland, said he was unsure how the average $21,000 a year broke down into domestic travel used by him or by his wife.

"I really don't keep track of these things. I just follow the rules and I really haven't got any comment on it at all."

Sir Geoffrey Palmer declined to comment, as his tight schedule meant he could not "usefully engage with this issue".

Moore was overseas, and could not be reached. Neither Rowling nor Shipley answered calls.

A spokesman for John Key said: "The prime minister has not considered his use of any post-Parliament entitlements. This is a matter for well into the future.

"These are long-standing entitlements, and they reflect not only the contribution made by past prime ministers, but also the fact that having held the office ... creates ongoing obligations for them."

BY THE NUMBERS

Travel spending from July 2011 to June 2014:

Jim Bolger and spouse Joan✓: $111,138.

Dame Jenny Shipley and spouse Burton✓: $70,687

Helen Clark and spouse Peter Davis: $64,055

Sir Geoffrey Palmer and spouse, Margaret: $33,715

Mike Moore and spouse Yvonne: $26,068

Sir Wallace "Bill" Rowling's surviving spouse, Glen: $11,541