Emergency services were called to the Opal Tower on Monday afternoon following reports residents of the Sydney Olympic Park building had heard and seen cracking throughout the morning.
Residents have not yet been told when they will be allowed back in the building, if at all.
One of the residents told Nine News that he had heard a "big bang", as though something had "snapped" inside the building, which only opened four months ago.
An exclusion zone with a radius of half a mile was established around the building, forcing the evacuation of neighboring buildings and the closure of roads and a train station, Sky News Australia reported.
"The number one priority for us is the safety of people-both the people inside the building and people in surrounding areas", Detective Supt Rogerson said, according to AAP. In addition, you could feel when the Wind is strong, like the building was moving.
"Hopefully it won't take longer than hours", Fire and Rescue Acting Inspector Greg Wright said of the investigation.
The 36-story high-rise building was evacuated over concerns over structural instability.
A large crack was found on the 10th floor of the building, with emergency services and engineers monitoring the situation overnight, with initial fears of a building collapse.
Hundreds of residents of a newly constructed Sydney apartment building are spending Christmas morning elsewhere as they await the all-clear from authorities to return home. They were not allowed back into their homes but were sent to an evacuation centre in central Sydney-the Royal Hall of Industries.
The website for the Opal Tower says the building has 392 apartments, commercial spaces, a childcare centre and community centre.
The building was only completed in March and opened in August, and cost $165 million to build by developer Ecove, which built numerous others nearby.
It was developed by Ecove, which also built many other new towers in the suburb along with One30 Hyde Park tower in the Sydney CBD.