As Rex Airlines enters into voluntary administration, some Australian politicians have taken aim at rival carriers Virgin Australia and more specifically Qantas for their behaviour in the aviation sector.

The regional carrier removed the option for travellers to book flights on some routes on Tuesday afternoon, after having halted trading on the ASX on Monday.

Come Tuesday night it was announced Rex Airlines had entered into voluntary administration, with Ernst and Young appointed administrators.

Earlier on Tuesday night, Shadow Transport Minister Bridget McKenzie told 7.30 the potential demise of the airline would be a massive blow for regional Australia.

"Rex plays an incredible role in connecting the 7 million of us that don’t live in capital cities, to the rest of Australia."

Rex will at this stage continue to fly regional routes but its flights between major airports are cancelled, and the group's domestic fleet of Boeing 737 aircraft are all grounded.

Those regional routes, according to independent senator Rex Patrick, are vital to not only transport but all aspects of life in regional Australia.

"Regional airlines are the lifeblood of these communities. They provide connection in terms of education, medical, business and indeed family connections," Senator Patrick told 7.30.

"When you take away that connection, we end up seeing professionals leave."

Senator McKenzie accused Qantas of deliberately putting Rex under financial pressure.

"As soon as Rex announced that they were going to take it up to Qantas and seek to provide more competition on the Melbourne-Sydney-Brisbane ... and other capital city routes, Qantas decided to fly and make a loss into those markets and put Rex under more financial pressure."

It was an allegation that was echoed by senator for Tasmania Jacqui Lambie, who frequently flies with Rex to her electoral base in Burnie.

"Trying to run one of the smallest airlines out of the air … that's exactly what they're doing," Senator Lambie said.

Senator Lambie then questioned whether, if Rex were to fold, Qantas would keep flying those routes.

When these allegations were put to Qantas by 7.30, the airline declined to comment.

Rex itself to blame?

Despite the politicians' allegations, aviation analyst Ian Douglas said Rex had put itself in this position.

"The capital city market entry was too small, too timid perhaps and at the same time their regional presence is supported by aircraft which are really getting towards the end of their life span," Dr Douglas told 7.30.

"The airline business is no place for timid people. It eats businesses up. The cash just keeps pouring out every time you push an aircraft back."

He said Rex's situation was vastly different to that of Bonza Airlines, which was placed into liquidation early in July.

"Nothing like Bonza at all," he said.

"Bonza's collapse was really [due to] flying very expensive aircraft, with a distribution that relied on an app on a phone that didn't even touch the Melbourne-Sydney market, where the value is.

"[They] had aircraft that were generally way too big for the rural routes that they were flying."

Dr Douglas said Rex could successfully navigate being put into administration, but it might require a retreat from the capital city market.

"My bet is that we will see Rex back to looking like Rex did before, which is flying the regional operations throughout rural Australia very effectively, probably not flying the jet services on the east coast."

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