Ryan said the plane's pilot informed passengers that staff had to manually enter bag data for every piece of luggage on all flights after the electronic system at the bag-drop failed.
An Auckland Airport spokesman confirmed there had been an internal IT problem at the airport but said there was no passenger congestion in the terminals.
"We're experiencing issues with our IT network which has had an impact on the internal Wi-Fi and the baggage system at the domestic and international terminals," he said.
"Our baggage system isn't operating at full capacity which at the international terminal building is causing a delay in the processing of luggage."
The spokesman said border processing of arriving and departing passengers was operating as normal.
He said the problem was being worked on with a view to resolving it soon.