Sydney apartment building deemed safe after collapse fears

An apartment building in Sydney's inner west has been deemed safe after residents were forced to evacuate due to collapse fears.

Residents on the ground floor of the building on Knocklayde Street, Ashfield were woken to the sound of cracking at about 3.30am, calling emergency crews when they saw tiles "popping up on the floor" and cracks in the walls.

At least 10 people were evacuated from six units and emergency crews were cautious not to cause any further structural damage.

There were also concerns the Westconnex tunnel, which runs underneath the building, may have been the cause of the damage.

Engineers have since determined the "popping floor tiles" were due to moisture underneath them, due to suspected plumbing issues.

Residents had been moved to an evacuation centre in the early hours, but after a five-hour investigation, engineers have deemed the site safe for residents to return.