Prime Minister John Key has restricted himself to flying business class on international flights. Photo / Greg Bowker

Prime Minister John Key has restricted himself to flying business class on international flights. Photo / Greg Bowker

Top Treasury officials have apologised for a mistake in pre-Budget documents that said the National Government was spending twice as much on travel as the Labour Administration it replaced.

It turns out National spent less.

Yesterday afternoon, the Treasury issued corrected figures showing Labour ministers' travel bill between December 2007 and February last year was $783,000 - much more than the $336,000 quoted in pre-Budget briefing papers to Finance Minister Bill English.

The figure of $739,000 for National ministers' travel costs from December last year to February this year was correct.

The faulty figures caused embarrassment for National and Prime Minister John Key, who was forced to defend the difference in the figures as being the result of a new Government seeking to build international relationships.

Labour leader Phil Goff used the figures to accuse National of hypocrisy, saying its ministers were happy to "spend up large on themselves" but demanded spending cuts from Government departments.

It is understood Treasury chiefs will apologise to Mr English and Mr Key.

Yesterday, Treasury Deputy Secretary Peter Mersi said he deeply regretted the error and apologised for it.

"We didn't meet our own high standards this time, and I'm looking into how that happened, to ensure that such errors are unlikely to happen again."

A spokesman for Mr Key said yesterday that the Treasury errors were disappointing but he was pleased the situation had been clarified.

The original table also understated the amount Labour spent on the chauffeur-driven car service VIP Transport and failed to point out that more than $500,000 of the total travel costs included that service.

The breakout of the VIP Transport costs shows National ministers were using the cars less than Labour - the monthly figure for Labour last year was $618,000, growing to $705,000 a month in the three months before the November election.

National's average for its first three months in office was $573,000.

In the pre-Budget briefing, the Treasury also relied on the incorrect figures when it said the new Government had "accentuated" cost increases in ministerial services and suggesting ministers cut their spending "to send a strong signal ... that ministers are fully committed to fiscal responsibility".