Sydney Airport passengers delayed by up to two hours after control tower evacuation

Passengers at Sydney Airport faced delays of up to two hours overnight after the air traffic control tower was earlier evacuated, grounding planes and preventing landings.

Firefighters were first called to the tower at 11.40am, following reports that smoke could be detected.

Two Fire and Rescue NSW crews attended the scene – assisted by the airport’s in-house fire team – and approximately 20 people were evacuated from the building as a precaution.

Fire and Rescue NSW Superintendent Bryce Jonas told 9news.com.au that crews quickly discovered the source of the smoke.

“When crews arrived they searched the tower and found no sign of fire. They then used thermal imaging cameras to detect the source of heat causing the smoke, and found it came from a battery backup system for the tower’s computers that had overheated,” Supt Jonas said.

“Crews removed the battery system, took it outside and hit it with a carbon dioxide cylinder.

“After that they let everyone back in, all under an hour. No injuries occurred.”

During the evacuation, all control of the aircraft in the airspace above Sydney was handled by Melbourne airport.

Planes have now resumed normal operations, with some flights beginning to land and take-off following the delay.

Despite that, Virgin Australia told 9News it was forced to delay eight flights and divert five as a result of the incident.

Jetstar has had to divert four and delay several more, and its customers - along with Qantas customers - are tonight facing the longest delays.

Brandon Livesay told 9news.com.au earlier that passengers were being informed over the airport’s loudspeaker that an “incident” occurred at the tower.

"'The airport is still shut down due to an incident at the traffic control tower' is what was coming through the speaker,” said Mr Livesay.

“My flight is postponed and looking through the window no planes are moving on the tarmac.”

Further delays are expected to continue into tonight for passengers flying out of Sydney.