The airport is expected to remain busy throughout the upcoming Easter long weekend followed by the Anzac Day weekend, with domestic travellers being advised to arrive two hours early.
Qantas CEO Alan Joyce says delays at Sydney Airport which began last week, are in part because up to half the workforce is isolating due to COVID-19.
"We're getting absenteeism of around 20 per cent, maybe some days in some areas up to 50 per cent, and that means that we can't open up all the security lanes," he told ABC TV on Monday.
"I want to apologise to all of our passengers - on behalf of the airports who do the security, on behalf of the airlines to having to deal with this," he said.
The decision to scrap the isolation requirement for airport workers who are close contacts made by NSW Health Minister Brad Hazzard will help to ease staff shortages, he said.
"We're also seeing that passengers are rusty in travelling as well.
"I just came back from a trip from the United States. I left my passport in my hotel safe," he said.
He urged passengers to be patient, saying staff were working well in tough circumstances.
Darwin woman Michelle Murphy said she endured a bit of a wait at Sydney Airport on Monday but had received multiple texts before her flight warning her to arrive early.
Traffic around the airport was heavy at 6am, she said, and while travellers could self-check-in to flights, the lines to drop off baggage snaked through the airport and took her about 45 minutes to clear before she reached security.
"They were calling flights with about 10 or 15 minutes before boarding to get them out of the queue (and) into security, where they still had to wait and to get through," she said.
"It wasn't chaotic. Everyone was well behaved.
"Everyone saw the line, jumped in the line and was polite and friendly and stuff.
"If you don't listen to the advice … I'm sorry that's on you for not actually listening to it."
Ms Murphy said she caught flights throughout the pandemic and the growing number of passengers in airports came as a bit of a shock.
There were delays in both domestic terminals on Monday morning however the backlog of passengers started to clear about 8.30am, a spokesperson for Sydney Airport told AAP.
"There is some delays at some airline check in desks, but they're getting through those (lines) and getting people to those security check in points."
6°C