Authorities have drawn no link between the construction of a major underground road tunnel and the early-morning evacuation of 10 people from a block of flats in Sydney's inner west.
But at least one resident isn't convinced.
Fire and Rescue NSW were called to the three-level Ashfield block in Knocklayde Street about 3.30am on Friday amid fears it could collapse.
Emergency workers were told brickwork in a unit in the building - which sits almost directly above the M4 WestConnex tunnel - had cracked and tiles had lifted from the floor. Internal doors were also stuck.
The building, which is about 20 years old, has since been deemed safe for re-entry.
Belinda Wilson, who has lived in the complex for 20 years but was not required to leave this morning, believes the cracks are a "WestConnex issue".
"There's been minor cracking everywhere since the tunnel went in," Ms Wilson told reporters on Friday.
"When all the drilling was happening before the WestConnex, you could feel the vibrations that went on for months.
"How can one bathroom make a whole building be structurally unsound? (We're) highly concerned and we obviously want more information about what's happening."
FRNSW Superintendent Adam Dewberry said there was no established link between the issues at the block and the location of the WestConnex tunnel.
Specialist firefighters from Liverpool Fire Station were rushed to the scene and set up laser measuring devices to monitor for building movement.
"It was just that initial precaution to make sure everyone was safe in the first instance," Supt Dewberry said.
"They are satisfied at this stage that the building is very stable.
"The cause of that very small area, which has been impacted with that floor area with the tiles and the cracking in the walls, that'll be investigated."
NSW Police Detective Acting Superintendent Despa Fitzgerald said police had also been on the scene and responded to reports of cracks in walls and tiles.
She said police would remain in place for much of Friday morning and said WestConnex staff were on site to determine potential issues stemming from the tunnel.
"One of the residents did say he heard some growling and some movement. That has subsided," Det Acting Supt Fitzgerald told Sydney radio 2GB.
A Transport for NSW spokesman said the organisation was monitoring the residential building, with government engineers on site to determine what caused the issue.
The spokesman said Transport for NSW and WestConnex would assist with any investigations if required and the new M4 tunnels would continue to operate as normal.