"Even by Perth Airport's standards, this is extraordinary behaviour," Qantas said in a statement.
"Protecting your interests is one thing but parking a bulldozer in front of an aircraft while saying you're 'working to secure an agreement' is ridiculous. It's no way to treat a customer of 20 years. This kind of action is deeply worrying for all users of Perth Airport."
Qantas said it has its "own dispute" with Perth Airport over what it described as "excessive charges". That brawl has been in court for more than a year.
"As part of that, they refuse to negotiate and pay up on the terminal they have effectively taken back from us, which is valued at well over A$150 million. How would they feel if we took the same approach to collections as them?" Qantas said.
Extraordinary scenes unfolded at Perth Airport yesterday afternoon, as a number of vehicles – including a bulldozer – were moved to block four planes.
"Virgin has significant outstanding invoices from Perth Airport for airfield and terminal use charges – money the airline had already collected from its passengers and the FIFO sector," a Perth Airport spokesperson said.
"While Perth Airport is working closely with administrators, it also needs to protect its own interests. Perth Airport has taken liens over a number of Virgin aircraft – a standard practice in these situations."
A lien is term that describes a legal claim to property that's made in order to satisfy a debt.
In a statement, Virgin Australia said: "We are aware that Perth Airport has restricted access to our aircraft and the Administrator is dealing directly with Perth Airport on the matter. There is no impact to scheduled flights."
T1 Terminal at Perth – Virgin's base there – has been closed for weeks because of coronavirus.
It is operating some charter flights from a different terminal to service fly-in, fly-out mining workforces in Western Australia.
The company owes $6.9 billion to some 10,000 creditors, according to an initial review by administrator Deloitte.
That sum includes about $2.3 billion of secured debt, $2 billion of unsecured bonds, $1.9 billion of aircraft leases, $450 million owed to employees, $167 million to trade creditors and $71 million to landlords.
