Auckland Airport and biosecurity officials have apologised for the delays passengers have been experiencing at the country's biggest international gateway.
They are asking for patience at the start of the school holidays, with 15,000 passengers expected to pass through the facility tomorrow.
This week, passengers had complained about long queues to get through the system.
Auckland Airport chief operations officer Chloe Surridge told RNZ's Nine to Noon that passenger numbers were back to pre-Covid levels and the high number of flight arrivals during peak times - combined with staff shortages due to illness - had caused the delays.
The peak times for delays in arrivals were between 4pm and 7pm, and then around midnight.
"It's certainly not the experience we would want - not just for Kiwis coming home but also for international visitors coming into the country," she said.
The average wait to get through customs, immigration and biosecurity checks in off-peak hours was 30 minutes.
"At the higher end, we do see people waiting in a queue for an hour, and on Sunday that was around two hours."
Surridge said there were many factors causing the delays.
"From the minute the plane takes off at its home port there could be delays. There may be weather along the way, and when it lands it could be off-schedule.
"On Sunday that's exactly what we saw: we had eight aircraft all arriving late, which impacted the flow of people through the building. It was almost double the amount of people expected at any one time."
The delays on Sunday had been compounded by sickness among biosecurity and baggage handling staff.
As arrivals number increased, however, it was not just about having "bodies on the floor", she said.
"We do need to make sure that they are trained well - these are highly regulated organisations such as civil aviation security, and that does take time."
Planning for the school holidays peak started six weeks ago, with co-ordination between airlines, ground handlers and border agencies - "all of us working together to see what's coming down the pipe and resourcing effectively for those peaks," Surridge said.
Auckland Airport was committed to reducing wait times in arrivals, she said.
"We have improved by 14 percent over the past six months. It's still not where we would want to be, but there are certain things we're doing together."
Surridge said anyone preparing to travel through the airport needed to be prepared.
"It sounds basic, but make sure you've got your documents ready, make sure you're checking the motorways, and check with your airlines to make sure there are no delays. If you [know you will] need assistance, call your airline in advance."
Departing passengers needed to give themselves time to get through security checks and could reduce delays by taking any liquids moer than 100ml out of their hand luggage.
"Two hours before your flight departs is a great time to arrive at the airport."
The airport had systems to process international arrivals with "tight" domestic connections more quickly, Surridge said.
Staff were also trained to help people needing assistance - such as the elderly, children and those with infants - and process them faster through arrivals.
"If you're stuck in a queue and you need assistance and you think you're going to lose your place [in line], just look for our people and they will help you," she said.
Biosecurity New Zealand MPI northern regional commissioner Mike Inglis defended the long delays for arriving passengers.
"We've got these biosecurity checks in place to protect our primary sector. It's a $57 billion-industry and we need to make sure we're not letting in damaging pests and diseases."
They had planned for increased demand by recruiting 100 officers in Auckland over the past 18 months, and had brought in extra staff from other parts of the business in the lead up to the school holidays.
Biosecurity had launched a trial with Air New Zealand today to process low-risk passengers more quickly.
Inglis advised passengers to consider carefully the items they were bringing into the country.
"If you are bringing in risk items, make sure you declare them. If you do have a lot of food that's allowed, it will take longer to process. We're searching and x-raying because we definitely do not want food and mouth and these catastrophic diseases coming in."
He also advised people to make sure family and friends who were coming from overseas were aware of the requirements.
"Make sure you declare. If you have nothing to declare, state that. If you do not need to bring stuff into Aotearoa, then don't bring it."
