Up to 160 residents of a high-rise unit block in Sydney's south face another two to three nights out of home after a crane collapsed onto the side of their building.
Authorities have begun investigating what caused the Sunday morning incident at Wolli Creek as engineers assess how to safely dismantle the crane, which smashed into a top-floor penthouse apartment of the at least 10-storey building, crushing the balcony.
It comes as a construction union calls for a halt to the use of Cantilever cranes until independent engineers' reports can prove they have been put together correctly.
All residents of the apartment complex on Brodie Spark Drive were evacuated when the crane, which firefighters estimate is about 30 metres tall, toppled on Sunday.
They could be forced to remain in temporary accommodation until at least Wednesday, with contractor Probuild estimating it could take another two to three days to safely dismantle the crane.
The company's NSW managing director Nick Gaudry on Monday told reporters a plan for the crane's removal was still being finalised but he expected it would involve the use of three mobile cranes.
He said they were still investigating what caused the crane's collapse.
NSW Police acting superintendent Scott Bingham told reporters the crane hadn't moved since its collapse but they were still working to ensure it was secure before they pulled it down in stages.
NSW Fire & Rescue Superintendent Josh Turner said authorities were working to check the integrity of the building, following the incident.
"We had to isolate the power and gas to the building because we're unsure about the damage at this stage," he told AAP.
The Construction, Forestry, Mining and Energy Union on Monday called on building sites across the state to temporarily stop using the cranes.
"We have no doubt that this particular crane is being under-engineered," state secretary Brian Parker told AAP.
"We have had this concern for a long period of time ... and it is putting all these lives at risk, including the public's."
Mr Parker said the union would not accept any report that wasn't completely independent.
Residents from surrounding unit blocks, who were also evacuated were allowed back home on Sunday night.
No one was inside the crane at the time of the crash.
Two people injured in the incident were taken to St George Hospital, with one of them suffering a leg injury, an ambulance spokesman told AAP.
Brodie Spark Drive and Magdalene Terrance remain closed to traffic.