Sydney flights backlogged after blackout

AAP

Power has been restored at a Sydney airport terminal but not before an outage caused a huge backlog of flights that has left many passengers stranded and uncertain about their travel plans.

The T2 terminal at Sydney Airport was brought to a standstill on Friday just after 8.30am, with the loss of power causing delays for passengers at check-in and screening.

The affected airlines included JetStar, Virgin, Rex and Tiger.

Delays were so bad during the morning that Virgin Australia advised its customers to avoid travelling to the airport.

It has since advised passengers that Virgin flights have recommenced, but there will be delays and cancellations.

Marie Organ and husband Greg, who have been in Sydney for a week, are trying to return to their home on Queensland's Sunshine Coast to make it to work on Saturday.

They've been told by Jetstar they'll be put onto a flight leaving Sydney on Sunday.

"Every carrier is trying to push their flights until tomorrow or the next day," Greg said while waiting for more than an hour to speak to a Jetstar representative over the phone.

Another passenger, Ash Druery, is trying to work out what he's going to do after his flight home to Hamilton Island was cancelled.

He was waiting for Jetstar to call him back to arrange accommodation as he's been put on a flight leaving Sydney on Saturday morning.

"Because there is such a backlog with how many Jetstar flights have been cancelled the phones are on a half-an-hour delay now," he told AAP.

"It's just a waiting game."

He's also due at work on Saturday, but said he would "have to cancel that as well."

"It's frustrating but I've got no control over it," he said.

The 32-year-old was understanding of the situation: "They've got 20,000 people trying to go on holidays and go home so they're doing what they can."

Like many others at the airport, he's been given a flight but has nowhere to stay on Friday night.

"I'm not going into the city. It'll cost me 20 bucks to get in there and then 200 (dollars) at the cheapest for a room."

Power has now been restored at T2 domestic terminal, Sydney Airport said in a statement released after midday.

"Sydney Airport has identified an issue with a substation, which caused the power interruption and affected back-up power sources."

The South Sydney NRL team was caught up in the drama, with the Rabbitohs due to fly to Townsville for Saturday night's match against North Queensland.

"Great day to be stuck at #sydairport #torture," South Sydney superstar Greg Inglis tweeted.

The outage comes as NSW school holidays are due to start on Friday afternoon.

Passengers are being advised to check their airline's websites for flight information.