Further passenger chaos at Atlanta airport

Passengers have been stranded after hundreds of flights were cancelled following a power outage at Atlanta Airport.

Hundreds of flights were cancelled and long lines snaked throughout the world's largest airport after a weekend power outage at Atlanta forced the cancellation of over 1,400 flights just days before the start of the Christmas rush.

A fire in an underground service tunnel brought Hartsfield-Jackson Atlanta International Airport to a stand still on Sunday and power was not fully restored until about midnight.

It meant thousands of travellers were forced to wait on planes or in the terminals while disabled people had to be carried down stairs and escalators in the chaos.

Inbound flights were diverted to other American cities and outgoing flights were halted.

A spokesman for Delta Air Lines, which has its hub in Atlanta, said the majority of its stranded passengers had been booked onto other flights on Monday.

Spokesman Michael Thomas said he expected said the airline would be "largely if not completely" back to a normal schedule by Tuesday, well before the peak travel weekend ahead of Christmas Day.

Georgia Power's top executive issued an apology, saying he realised the power outage had inconvenienced thousands of people.

Delta cancelled about 1,000 flights on Sunday and another 400 Monday while American Airlines saw 24 cancelled departures and an equal number of arrivals, spokesman Ross Feinstein said.

Some passengers complained about a lack of information from airport officials and little help from first responders to get the disabled and the elderly through the airport without the use of escalators and elevators.

"They had these elderly people, handicapped people lined up in wheelchairs," stranded passenger Rutia Curry said. "The people were helpless. They can't get down the stairs. It was just a nightmare."

Feinstein said the American was back on a normal schedule by late Monday morning.

At Southwest Airlines, about 70 Atlanta departures out of 120 scheduled for Sunday were cancelled, an airline spokesman confirmed.

United Airlines and JetBlue Airways were among the carriers reporting delays or cancellations.

Hartsfield-Jackson, which serves 104 million passengers a year, is the world's busiest airport, a distinction it has held since 1998.

The airport serves an average of 275,000 passengers daily, according to its website. Nearly 2,500 planes arrive and depart each day.