Perth Airport has seized a number of parked Virgin Australia aircraft because of unpaid invoices, with the airport saying it must "protect its own interests".

Dramatic images show a bulldozer blocking one plane on the runway at the airport.

It is the latest development in Virgin's potential demise - the biggest collapse of an Australian business amid the fallout from the coronavirus pandemic.

Virgin Australia is estimated to owe more than $6.8 billion to its more than 12,000 creditors, Federal Court documents filed by administrators Deloitte on Friday say.

As well as the bulldozer, trucks and portable stairs were last night positioned right in front of aeroplanes to stop them taking off.

"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 sector," an airport spokesperson said on Friday.

"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."

The airport did not specify the value of the dues.

The aircraft had been parked for some time and were not currently being used for flights.

The bankrupt airline is currently flying a skeleton schedule under its regular management team as administrators seek a buyer for the entire operation.

Administrators, Deloitte, are liable to pay leases on its aircraft starting April 28.

They are seeking court orders for an extension of up to four weeks from their appointment to decide if leased planes were required for continuing operations of the business.

Virgin Australia entered voluntary administration on Tuesday as a result of plummeting demand because of flight restrictions.

Rival Qantas slammed Perth Airport's decision to seize Virgin aircraft as "ridiculous" behaviour and said it was "deeply worrying" for all users of the airport.

Earlier this week, CEO Paul Scurrah said the announcement that the carrier was in administration was tough, but the plan was for the group to survive the economic impact of the coronavirus pandemic.

At least 10 potential investors, some international, are understood to be circling the failed airline.

"This is a tough day for our airline ... (but) we're certainly not collapsing," he told reporters.

The coronavirus pandemic was responsible for the worst aviation crisis imaginable but Virgin would be back, Mr Scurrah said.

Virgin owes nearly $7b to thousands of creditors, according to reports.

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Source: 9News