Hundreds of Sydney residents evacuated after crack appears in 30-storey tower

Hundreds of Sydney residents have been evacuated after hearing cracking sounds from inside a 30-storey-high building.

Residents first began complaining about the noises on Monday morning and emergency services were called in the afternoon, 7News reports.

Firefighters have reportedly discovered a crack in the high-rise apartment block in the suburb of Olympic Park.

Residents from nearby properties have been evacuated as emergency services assess whether the building poses a risk of collapse.

Aerial footage of the area shows emergency services setting up tents as police redirect traffic and pedestrians.

The building affected is The Opal, which cost $165 million to build and has 392 apartments, commercial spaces, a childcare centre and a community centre.

Construction finished on the building in August.

Police say it has shifted one or two millimetres as a result of the issue, but there has been no further movement, News.com.au reports.

Residents who have nowhere to go were sent to a temporary shelter at the Sydney Showgrounds.

"Police and emergency services are also working with the building managers to put contingencies into place for the affected residents, if needed," NSW Police Force Acting Assistant Commissioner Julie Boon said.

"Our aim is to ensure the safety of everyone involved before allowing residents to return."

Newshub.