Education Minister Dan Tehan says his colleague, Finance Minister Mathias Cormann, followed the rules when he spent $37,000 on flights within a day in 2018.
Finance Minister Mathias Cormann was acting within the rules when he booked flights costing $37,000 to sway crossbenchers towards big business tax cuts last year, Education Minister Dan Tehan says.
Senator Cormann flew from Canberra to Adelaide and then onto Perth on a defence jet on June 22 as no commercial flights were available to facilitate the journey, the ABC has reported on Friday.
The flights came the day after the federal parliament approved the government's personal tax cuts and as the coalition was trying to rally Senate support for proposed tax cuts for big businesses.
The government has since shelved the corporate taxes.
Mr Tehan says Senator Cormann had been "hellbent" on getting tax cuts over the line and made the trip to Adelaide to negotiate with crossbenchers.
"What that trip was about as I understand, was making sure that we were doing everything possible to see Australians pay less tax," he told ABC TV's Breakfast on Friday.
The education minister said there are rules everyone must follow in taking flights on special purpose aircrafts and Senator Cormann was within them.
"The Australian taxpayer can look at that and say it was within the rules, within the guidelines, and also he was there on business."
Senator Cormann flew back to Canberra from Perth for another parliamentary sitting week on June 24 at a cost of $1,808.02.
The ABC reports his special aircraft booking on June 22 was the only one of 193 made in the first half of 2018 that involved a single passenger.
Mr Tehan said he has used the aircraft to travel to Tenant Creek for work but believes he has always had staff members with him.
Greens Senator Sarah Hanson-Young said she wasn't sure the spending "would pass the pub test".
"$40,000 sounds like a lot of money for a meeting that he was obviously very desperate to do but didn't result in very much," she told ABC Radio National on Friday.