Records indicate Jim Prentice racked up more than $400,000 using government aircraft during his 4½ years as a federal cabinet minister, Alberta's NDP says.

New Democrat Deron Bilous says some of the charges seem needlessly extravagant, including near-empty flights, deadhead flights and short-haul excursions when there were plenty of commercial options.

In one case, Bilous said, Prentice flew himself and two staff to Norway at a cost of almost $42,000, when commercial flights were available for about half that amount.

Prentice, who was unavailable for an interview when contacted by CBC News on Wednesday, issued this statement in response to the allegations:

"Acting in the capacity as Minister in the important cabinet portfolios of Indian and Northern Affairs and Federal Interlocutor for Métis and Non-Status Indians, Industry, Environment, and as Chair of the Operations Committee, I only used government aircraft in order to carry out my official duties, and only when commercial alternatives were not available at the time that I had to travel to complete those official duties.

"The federal government has very clear and stringent rules about use of government aircraft; it is only permitted when there is no commercial alternative at the time of travel and when proposed travel has been approved by the Prime Minister’s Office and deemed necessary in order to carry out official government business. During my time in Ottawa, I always followed these rules implicitly,” the statement said.

Prentice, one of three candidates vying to replace Alison Redford as Progressive Conservative leader and premier, has promised to end the extravagant spending — including the frequent use of government planes — that helped lead to Redford's resignation in March.

Calgary MLA Ric McIver and Edmonton MLA Thomas Lukaszuk are also vying to be the next Alberta PC leader. Dave Hancock has been serving as the interim premier for Alberta until the party holds its leadership vote in September.