In a statement on the Rex website, it said Virgin Australia was offering to assist customers affected by the cancellations.
While Rex says it'll contact customers, the news has created uncertainty for some travellers.
Here's what you need to know.
All flights between major airports on Boeing 737 planes are cancelled.
That includes the following routes:
Flights on Saab 340 planes to destinations Rex classifies as "regional" are still going ahead, it said in a statement.
"Regional flights are unaffected by the administration and will continue to operate as normal."
It said flights for those routes can still be booked via its website or travel agents.
You should be able to book the same route on an equivalent Virgin Australia service free of charge.
But this won't happen automatically — you'll have to go through Virgin before August 14 to do this.
Customers travelling in the next 48 hours were told to contact the Virgin Australia Guest Contact Centre on 13 67 89.
But if you are flying later, you can access the rebooking request form here.
"Don't turn up to the airport for your flight unless you have already spoken with Virgin Australia, and received confirmation of your alternative travel arrangements," Rex said in a statement on its website.
Rex said it would contact customers directly.
Virgin Australia chief executive Jayne Hrdlicka said her company was aware of 100,000 customers affected by flight cancellations, with 34,500 already submitting applications to rebook their journey.
Of those, 5,000 people have already been rebooked on alternative routes.
Here is what the Rex website says about what happens in the event there is no Virgin replacement flight available for a cancelled service.
When a Rex flight is cancelled, Rex will search for alternative means to get you to your destination.
It says it will attempt to:
"If you accept alternative transport from us, we would have been considered to have fully discharged our responsibility with regards to your air ticket.
"If you refuse the alternatives provided or if no alternatives are provided, then we will refund the remaining unused portions of your itinerary on Rex to the original method of payment (which may be your travel agent)."
It says to call the Customer Contact Centre on 13 17 13.
Travel services, such as flights and tours, come with basic consumer rights known as consumer guarantees.
Rex Airlines, Australia's largest regional and domestic airline operator, enters administration.
This includes the guarantee that services will be provided within a reasonable time after being delayed or cancelled.
According to the ACCC, a travel service provider must give the option of a refund if it can't provide a replacement service for a cancelled flight in a reasonable amount of time.
The ACCC cannot resolve individual complaints about delayed or cancelled travel services.
Regional Express, Rex for short, is the primary subsidiary of Regional Express Holdings and is an ASX-listed company.
Rex was formed by a consortium of individuals comprising Singaporean investors and a collection of Australian private investors in 2002.
Businessman and former defence engineer Lim Kim Hai is the main shareholder and founder.
In recent months, Rex has also been caught up in internal strife that came to a head in a boardroom coup resulting in Mr Lim's replacement as executive chair.
The airline's chief executive officer is Neville Howell.
Voluntary administration is an insolvency procedure in which a company brings in someone from outside to manage its affairs because it is in financial trouble.
The managers brought in are called an administrators.
They assess all the options available and generate the best outcomes for the business owner or company, the Fair Work Ombudsman says.
But, if it's not possible to save the company or its business, the administrator will manage the company's affairs to get a better return for creditors, the Australian Securities and Investments Commission (ASIC) says.
In the case of Rex Airlines, consultancy firm Ernst and Young Australia (EY) is acting as the administrator.
It aims to "restructure the business so it can continue to service regional Australia", a spokesperson for the firm said.
Administrators for Rex Airlines have told employees that the company is unable to pay their wages due to its "very perilous financial position".
The ABC understands an additional 250 employees are to be made redundant in the company's Regional Express division — which operates flights in regional and rural Australia — despite it remaining operational.
The Transport Workers Union's Michael Kaine said administrators told him up to 610 staff would be made redundant.
Virgin says it'll look to hire former Rex workers.
"All Virgin Australia jobs that are open will get prioritised for Rex affected employees," Virgin Australia's Ms Hrdlicka said.
"We're intending to bring on three 737s from the Rex fleet. We can bring more Rex employees to new jobs, and it's important to make sure people in our industry are as well supported as they can be."
EY and Rex did not confirm the number of expected job losses when contacted by the ABC.
Rex says its frequent flyer points will be frozen while it is in administration.
Customers will not be able to use or accrue points during the administration period.
In the event of a successful restructure of the business, accrued points may become available again.
Posted Wed 31 Jul 2024 at 1:45am Wednesday 31 Jul 2024 at 1:45am Wed 31 Jul 2024 at 1:45am , updated Wed 31 Jul 2024 at 7:01am Wednesday 31 Jul 2024 at 7:01am Wed 31 Jul 2024 at 7:01am
