Travellers are experiencing long delays at Auckland Airport, apparently because of a computer problem.
NZME radio producer Max Middleton said the crowds were building up at the international terminal.
"No flights are being able to be checked in at the moment," he said.
"The airport is chaos and no one seems to know what's going on."
Kate Holdsworth tweeted from the airport "no one can check-in".
"Already queued for an hour and not moved. No one can check in. Not exactly what you expect when you've paid for Business Class," she posted.
The Herald has asked Auckland Airport for comment.
Meanwhile, travellers across the ditch are also experiencing similar issues.
Kiwi Graeme Underwood was at Melbourne International Airport and said it was "chaos".
He was meant to be flying back to Auckland this morning with Air New Zealand, but had been unable to check in.
All airlines were affected, he said, and a staff member told him it was a worldwide check-in issue.
"I am not sure what is happening but the airport is at a standstill."
Air New Zealand staff were handing out meal and drink vouchers to affected customers, he said.
"They are doing a great job accommodating everyone, which makes you think we might be here for a while."
Jetstar issued a travel alert stating an "IT issue" was affecting their airport systems today, resulting in delays and cancellations to some domestic and international flights.