Thousands forced to flee after 'cracking noises' heard by residents in newly built Sydney tower block on Christmas Eve

Building has moved up to two millimetres, experts say

The Opal Tower at Sydney Olympic Park (EPA)

Thousands of people living in or near a newly built tower block in Sydney have been forced to leave after they heard cracking noises.

Experts found the 36-storey Opal Tower complex in the Australian capital’s Olympic Park had moved up to two millimetres, police said.

Firefighters and engineers were preparing to enter the building to examine what caused the reported cracks on its 10th floor and to determine whether the building was in danger of collapse.

“It’s not going to be done in minutes. Hopefully it won’t take longer than hours,” said fire and rescue acting inspector Greg Wright.

Police reportedly had to use heavy equipment to force open doors to allow residents to escape.

An exclusion zone with a radius of 1km was established around the building, forcing more than 3,000 people to get out, and the closure of roads and a railway station.

New South Wales police said the alarm was raised by residents who reported hearing “cracking noises” throughout the morning.

The tower, which looms over the central site of the 2000 Sydney Olympics, has 392 apartments, a retail area and a childcare centre.

Water and gas services were shut off, and the tower was being isolated from the power grid, Mr Wright said.

Meriton, the operator of the neighbouring building, which was completed only in August, warned residents that there was “potential for the tower to collapse”.

A resident of Opal Tower told the Nine News network he heard a loud bang as if something in the building had “snapped”.

Another told the Australian Broadcasting Corporation there were cracks on the building’s 12th and 13th floors.

“I’m concerned, of course,” he said.

“A few days ago the doors looked different, like they couldn’t close properly. And you do feel [movement] sometimes when there’s strong wind.”

People from Opal Tower and surrounding properties have been taken to an evacuation centre and it was not clear whether or when they would be able to return to their homes.

Additional reporting by PA