Riverina MP Michael McCormack has spent almost $500,000 on travel via private jets supplied by the Royal Australian Air Force over the course of six months.
A spokesperson for Mr McCormack said the flights were authorised by the Defence Minister within the guidelines established by the Department of Finance, including the requirement to "justify why a commercial flight is not viable".
Department of Defence records tabled in Parliament last week show that Mr McCormack used or commissioned 95 journeys via 'special purpose flights' between July 1 and December 31 last year.
The cost to taxpayers of Mr McCormack's private RAAF travel was $393,474 while in his capacity as Deputy Prime Minister and Minister for Infrastructure, Transport and Regional Development, and $100,882 for flights while he was Acting Prime Minister.
Between July and December 2017 Mr McCormack's predecessor as National Party leader, Barnaby Joyce, spent $176,476 on RAAF private jet flights as deputy prime minister and $27,140 as acting prime minister.
My Joyce was out of Parliament for about two of those six months due to the Section 44 crisis over dual citizens being ineligible to stand for election.
A bill of $101,207 was run up for 24 flights that flew with no passengers in order to make aircraft available or return them to home base at Canberra.
The bill included an empty flight from Canberra to Leonora in Western Australia that cost $20,240.
A spokesperson for Mr McCormack said the "positioning flights" with no passengers were also used by the RAAF for training.
"Positioning legs without passengers are utilised by Air Force crew for essential training and development, whilst still enabling the subsequent special purpose flight," the spokesperson said.
"There is no minimum distance required for use of SPA [special purpose aircraft]."
The spokesperson said costs listed in the Defence report were based on an annual appraisal for operating the SPA fleet and "include ground handling costs, fuel, catering and other costs".
The cost of individual flights ranged from $175 for a flight from Wagga to Temora up to $14,720 for a flight from Sydney to Kalgoorlie.
Under the guidelines, MPs requesting special purpose flights must state what alternative transport options are available and why they would be unsuitable, as well as stating why the journey was important.
It is not suggest that any of Mr McCormack's requests were outside the guidelines.
Almost all of Mr McCormack's private flights were taken aboard a CL604 Challenger twin-engine jet, which can carry up to nine passengers with a crew of two pilots and one flight attendant.
Some of the flights used a modified Boeing 737 that can carry up to 30 passengers.
- Manufacturer: Bombardier
- Crew: Two pilots and one crew attendant
- Length: 20.9 metres height: 6.3 m Wingspan 19.61 m
- Weight: 21,863 kilograms (max takeoff)
- Cruise Speed: 870 kilometres per hour
- Range: 5600 kilometres
- Capacity: nine passengers
737 Boeing Business Jet
- Manufacturer: Boeing
- Crew: Two pilots, and up to 4 crew attendants
- Airframe: Length: 33.6 m height: 12.5 m Wingspan: 35.8m
- Weight: 77,565kg (max take-off)
- Speed: 850km/h normal operations
- Range: 11,390km
- Capacity: 30 passengers
Beechcraft King Air KA350 (B350)
- Manufacturer: Beechcraft
- Crew: Two pilots
- Airframe: Length: 14.2 m, height: 4.4 m Wingspan: 17.7 m
- Weight: 6894 kg plus 1600 kg payload
- Cruise Speed: 570 km/h
- Range: 3400 km
- Capacity: eight passengers