The air safety regulator will seek to extend the grounding of budget airline Tiger Airways until the beginning of August.
The Civil Aviation Safety Authority (CASA) has already suspended Tiger Airways' domestic services until Saturday, due to safety concerns.
CASA spokesman Peter Gibson says an application will be made in the Federal Court later this week to extend the grounding until August 1.
He says the authority has not had enough time to complete its investigation.
"Investigations into the safety issues with Tiger are not complete," he said.
"There's no way we could complete by them end of this week so we're going to go to the Federal Court and seek an extension to August 1 so we can finalise these matters."
CASA says if investigations are finished before August 1, the airline may be able to resume flying sooner.
Yesterday, the budget carrier succumbed to pressure from the Australian Competition and Consumer Commission to stop selling flights amid uncertainty about when the grounding will be lifted.
The consumer watchdog warned Tiger for continuing to sell tickets without alerting customers about the possibility of a ban extension.
Tens of thousands of travellers have been affected since the airline's services were abruptly brought to a halt on Saturday.
CASA suspended all Tiger flights after a second plane within a month approached an airport below the lowest safe altitude.
The authority had also raised a number of safety issues with Tiger in March.
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