Passengers have reported "gridlock" with "three hour queues" at Manchester Airport.
The airport has apologised for the disruption which it says has been caused by an ongoing IT system outage 'affecting some processes'.
Staff made passengers aware of the problems from around 6am on Tuesday 17 January.
At the time, delays were relatively minimal but have since backed up causing the terminals to become 'rammed'.
John Gregory, who was due to fly to Dubai at 1:10pm, said there were 'painful' delays at baggage drop-off.
He added that bags were all having to go through point where skis and other large objects would usually go through, making everything extremely slow.
Mr Gregory said: "We've been waiting three hours at the check-in, we've now been pulled out as they're calling flights through that are soon.
"All bags are having to go through one bag inspection as the rest aren't working. It's painfully slow.
"There are lots of staff on the ground trying to get things through but it's absolutely rammed here now. It's completely backed up."
Another passenger said that by 10:30am they had been waiting an hour-and-a-half to take off due to the IT outage causing baggage delays.
Information boards showing departures and other information are not updating, according to passengers. Some are not working at all.
Flight information is being delivered over the public address systems and by staff in the departures areas.
In an update this afternoon, a Manchester Airport spokesman said: "Due to the outage we are experiencing, we are aware Terminal 1 is currently much busier than usual due to delays to the check-in process in particular.
"While our teams work to resolve the problems affecting our systems, we are doing all we can to ease congestion within T1 and get travellers through the airport as quickly as possible.
"Staff are on hand to provide whatever assistance they can.
"Further updates will follow as soon as possible, and we thank passengers for their patience and understanding at this time.
"We advise passengers to check with their airline for up-to-date travel advice."
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