Air Force Chief Geoff Brown has flatly dismissed the usefulness of Environment Minister Greg Hunt's Antarctic whaling surveillance aircraft.
"The (Airbus) A319 is not suitable for that task," Air Marshall Brown told a Senate Estimates hearing on Wednesday.
"The word surveillance can mean many things," he said. "Surveillance out of a passenger aeroplane is a pretty limited operation."
He said the Air Force considered all options for the whaling surveillance task, including its P3 Orion and C-17 Globemasters, but found them unsuitable because they lacked the range to operate off the Antarctic coast.
"The recent announcement of the (Boeing) P8 will certainly give us capability to get down there because it's air-to-air refuellable, which the P3 isn't."
Air Marshall Brown was responding to questions from the Greens Senator, Peter Whish-Wilson, who has been pursuing the government over its whaling policy in estimates.
"I never expected that the final demolition of their plan's credibility would come from the Chief of the Air Force,” Senator Whish-Wilson said after the hearing.
Mr Hunt announced the A319 would fulfil the whaling patrol role last December, despite an election commitment to send a Customs vessel south to monitor the conflict.
Originally leased by his department's Australian Antarctic Division to fly personnel to Antarctica, he said the A319's purpose on the whaling flights would be to record incidents on the high seas.
"It will be to ensure there is a presence to make sure that there is no conflict between the parties,” Mr Hunt said. “It will also be to ensure that there is awareness from all parties that the world is watching.”
The leased long range aircraft has since conducted a single flight under the control of the Customs and Border Protection Service at a cost of $93,248, estimates heard.
It was absent from all three confrontations between Japanese whalers and conservationists so far this season, which occurred in the Ross Sea region, far south-east of Australia.
Sea Shepherd captain Peter Hammarstedt said in a plea to Mr Hunt that an Australian Customs vessel could have documented when the conservationists' ships were blockaded by whaling vessels towing steel wires.
"In the absence of any kind of enforcement down here, and as promises are broken, my ship is getting battered and my crew are getting pummelled." Mr Hammarstedt said.
A response was sought from Mr Hunt.