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.
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 rebuilding its workforce as domestic flights return, but Mr Hay said that's not the only reason.
"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.
