Domestic passengers around Australia are being advised to arrive earlier than usual as pandemic-related staff shortages continue to cause delays during the bumper school holidays ahead of the Easter long weekend.
A Sydney Airport spokesman said there are aviation industry-wide staff shortages around the world.
"We have significant COVID-related staff shortages and we're also working to rebuild our workforce in a really tight jobs market," the spokesman told AAP on Tuesday.
The airport expects the school holiday period, which includes consecutive long weekends of Easter and Anzac Day this year, will be the busiest time for domestic air travel in the past two years.
It is advising domestic passengers to arrive two hours prior to their scheduled departure, effectively doubling the usual waiting period.
Other airports along the east coast have delivered a similar warning to travellers.
Melbourne Airport warned on Friday there could be delays over the holidays and queues were expected during check-in and security screening.
Brisbane Airport has been telling domestic passengers to arrive two hours early since the end of March.
"We predict this coming Thursday to be our busiest day yet with more than 50,000 passengers expected," Brisbane Airport Corporation communications manager Rachel Bronish told AAP on Tuesday.
She said there has been similar numbers on some days recently but queues have been moving quickly, with the longest wait to get through security about half an hour.
Domestic passenger traffic at Sydney airport has nearly doubled in the past six months, general manager of operations Greg Hay said on Monday, however it has not returned to pre-COVID levels yet.
It is expected to reach up to 90 per cent of pre-pandemic traffic during the upcoming holiday weekends.
Queues at security checkpoints are also being exacerbated by the airport's security provider Certis Security Australia rebuilding its workforce as domestic flights return.
The company said it remains committed to supporting the airport's operations in a statement on Tuesday.
"As with many industries, (we are) dealing with the combination of labour shortages and the direct impact of close-contact isolation rules on our workforce.
"Our focus is on building up our team to ensure smooth check-in and security operations in the most efficient manner."
But Mr Hay said that's not the only reason people were taking a while to get through security.
"We've also noticed people are a little out of practice with security protocols, for example not taking laptops and aerosols out of their bag at screening points, which is contributing to the queues," he said.
Friday and Monday morning saw long queues forming at airport security and check-in counters, while departing passengers faced longer waits for their baggage to be transported from planes to carousels.
Australian Associated Press
Sign up for our newsletter to stay up to date.