A refuelling issue that grounded almost 70 planes at Perth Airport is under investigation as the threat of further cancellations looms.
Travellers heading to or departing the main West Australian airport were left in limbo on Saturday after a fuel load pressure issue in the supply system prevented planes from being refuelled.
Airport chief executive Jason Waters said the fault occurred in the facility's common distribution system, with external experts brought in to resolve the issue by Saturday afternoon.
Air was sucked into the distribution system, he said.
"Our engineers and technicians have worked through the evening and early hours of this morning to identify, repair, (and) retest the system," Mr Waters told reporters.
"We are now back to normal refuelling operations and obviously, we're very keen to see a return to normal operation."
By 4.30pm on Saturday, 68 flights had been cancelled because of the fault however delayed flights had been cleared.
Mr Waters said the fault would be subject to a full engineering review and investigation.
"I'd like to think by this evening and tomorrow we'll have it dealt with," he said.
"But given that we are talking about some long-haul flights and (with) the extent of the backlog, it might take some time."
It would be up to airlines to determine if any further flights would be cancelled as they worked to clear the backlog.
The cancelled flights included departures from Perth to Sydney, Darwin, Brisbane, Kuala Lumpur and Bali, and arrivals from the same locations.
Some arrivals were diverted to other airports including a flight from London which was forced to land in Karratha in WA's north.
The airport said it would work with airlines to clear the backlog to help passengers get to their destinations.
"We again thank both passengers and our airline partners for their patience and understanding," a spokesperson said.
Qantas issued an update for its passengers earlier on Saturday, explaining the cancellations and delays occurred because no fuel was available to any aircraft on the ground at the airport.
Affected customers were being contacted directly and all travellers were warned to check their flight status before heading to the airport.
Federal minister Matt Keogh expressed his frustration for passengers, saying it was a "highly stressful" situation.
"I feel for the passengers firstly, because whenever one is caught up with chaos at an airport it's highly stressful," he told reporters on Saturday.
Passengers departing from Perth on Saturday were urged to contact their airline for more information about their flights.
