Perth Airport is using heavy machinery and company vehicles to block a number of Virgin Australia aircraft from taking off over what it says are significant unpaid debts.

Key points: Perth Airport says Virgin owes $16 million for airfield and terminal use

Perth Airport says Virgin owes $16 million for airfield and terminal use Four planes are currently being prevented from taking off

Four planes are currently being prevented from taking off The airport says this is a standard practice in these situations

In a statement, the airport said while it was working with the airline to get through the coronavirus crisis, it had to protect its own interests.

Perth Airport says the debt-laden airline owes it $16 million in outstanding invoices for airfield and terminal use charges.

The airport has taken the planes as security, or what is known as a lien, on the debt.

Footage and images from the airport show a front-end loader and airport cars blocking planes on the tarmac.

Perth Airport said this was standard practice.

"Maintaining a two-airline system in Australia post-COVID-19 is absolutely essential for the aviation and tourism sectors, and the broader economy," a spokeswoman from Perth Airport said.

"Virgin has significant outstanding invoices from Perth Airport for airfield and terminal use charges — money the airline has already collected from its passengers and the FIFO [fly-in, fly-out] sector.

"While Perth Airport is working with the Virgin 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."



Four planes not currently in use

Perth Airport chief executive Kevin Brown told ABC Radio Perth the four aircraft that had been blocked were already in hibernation.

A front-end loader sits in front of a Virgin Australia plane, blocking it from leaving. ( ABC News )

"These four aircraft are actually not in service at the moment," he said.

"Two of them don't even have engines on them, one of them has an undercarriage issue, for several weeks it's been parked up.

"We of all people want to see a viable aviation industry in Australia, we want to see more than one carrier in Australia."

Mr Brown said Virgin Australia understood this was part of the process.

"They can access those aircraft if they need to do any maintenance on them," he said.

"But they have [a] debt recovery document that's been placed on those aircraft, and that was submitted to the administrator two days ago."

Current flights will not be affected

An airport spokeswoman said no flights would be impacted.

"The aircraft affected are not being used for current FIFO or interstate operations and have been parked at Perth Airport for some time now," she said.

"There will be zero impact on the state's resources sector.

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"At this point in time, we continue to facilitate Virgin's FIFO flights through T2 [Terminal 2] while we try to secure an agreement with the administrators.

"Virgin continue to fly around 180 flights a week through Terminal 2."

Virgin Australia — which went into voluntary administration this week — said it was aware of the situation and was working with the airport.

Qantas takes swipe at airport amid own legal dramas

Qantas, which is currently locked in its own battle with Perth Airport over airport charges, criticised the move to impound the planes.

In a statement, Qantas described the decision as extraordinary behaviour and deeply worrying for all users of Perth Airport.

"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," a statement from the head of external communications Luke Enright said.

"It's no way to treat a customer of 20 years.

"This kind of action is deeply worrying for all users of Perth Airport."

Mr Enright characterised Qantas's dispute, which is currently before the courts, as relating to "excessive" charges and claimed Perth Airport was refusing to negotiate over the use of Terminal 4, something the airport emphatically denies.

"They refuse to negotiate and pay up on the terminal they have effectively taken back from us, which is valued at well over $150 million," Mr Enright said.

"How would they feel if we took the same approach to collections as them?"

A Perth Airport spokesman said the airport had repeatedly tried to seek a commercial resolution with Qantas and had made multiple offers to achieve this, all of which were rejected.

"In relation to Terminal 4, we are following an agreed joint independent valuation process," the spokesman said.

"Qantas is fully aware that an independent valuer has been agreed and appointed because they have been involved in the process.

"We are puzzled by Qantas's latest comments and the motivations behind them."