TIGER Airways was in disarray following the extension of its flying ban to the end of the month and the shock resignation of its Australian chief executive.

The aviation industry safety authority will apply through the courts to extend its suspension of Tiger until August 1 as it trawls through masses of information regarding the airline's safety procedures.

The Civil Aviation Safety Authority (CASA) said it would go to the Federal Court in Melbourne either today or Friday to seek the extension.

While the scope of the investigation has not expanded, the safety issues are more complex than they initially appeared.

"The scope of the investigations remain pretty much the same but as we're working through it, we're finding that the issues are very complex, more complex than we first thought," CASA spokesperson Peter Gibson told the ABC.

Just hours after the flying ban was extended, Tiger issued a short statement saying its chief executive Crawford Rix will finish up at the airline on July 31.

His replacement is Tony Davis, the group president of Tiger Airways Holdings and the man who was sent from Singapore to lead the talks with CASA.

On July 2, CASA slapped a week-long ban on Tiger because it believed the budget airline posed a "serious and imminent risk" to air safety.

The now month-long extension throws serious doubts on the airline's survival in Australia.

Tiger said it would not oppose the ban extension but remained committed to getting back into the air as soon as possible.

It will refund fares to passengers holding reservations between now and July 31.

Mr Gibson said more questions were being thrown up as investigators went through Tiger's books.

"We have to make sure we fully understand the reasons why these problems have occurred - if they are systemic problems, problems with process and problems with safety systems," Mr Gibson said.

The authority is looking particularly at two landings in June - one at Avalon and the other at Tullamarine - in which the pilots approached too low.

"The investigation is a big task and one that could not be done within the original one-week time frame," Mr Gibson said.

"As you go through you get a better appreciation of the matters and that raises more questions.

"But that's not to suggest that we are finding anything untoward."

He said Tiger management had been cooperative and constructive during the investigation.

After pressure from the nation's consumer regulators, Tiger on Tuesday night suspended ticket sales for flights beyond Saturday.

A "bewildered" Australian Competition and Consumer Commission chairman, Graeme Samuel, said Tiger took too long to respond to the regulators' concerns.

"It's not a question of welcoming, it's a question of saying, well at long last they've responded," Mr Samuel said.

State and federal consumer regulators had warned Tiger that if it continued selling tickets for flights from Saturday, it needed to tell customers it was uncertain whether it would be flying and that it was dependent on CASA approval.

Tiger announced at 10pm (AEST) on Tuesday it was suspending sales and Mr Samuel said the airline's lack of response until that point was far from satisfactory.

"There was 48 hours there where despite the fact that they knew that our view was that to comply with the Australian consumer law they needed to provide this advice to customers. They simply for one reason or another didn't respond and didn't deal with that appropriately for customers.

"There were a large number of customers potentially who bought tickets on Monday and Tuesday who did not have that advice and warning given to them at the time that they bought the tickets."