Three workers were taken to hospital and 160 people displaced after a crane collapsed onto an apartment block in Sydney’s south.

The workers’ union, the CFMEU, condemned the incident as “not good enough” and called for a halt to the erection of cranes until investigations are complete.

Police were called to Brodie Spark Drive at Wolli Creek about 9.30am on Sunday, following reports a crane had fallen off one building and crashed into another.

Both damaged buildings were evacuated as well as residents in two surrounding buildings while it was decided how best to remove the crane, Fire and Rescue NSW spokesperson said.

More than 160 people were evacuated from their homes, with authorities unsure when it will be safe to return.

The salvage operation continued into the night, as emergency services worked with the property developer, Frasers Property Group.

Trains on the Airport Line between Central and Turrella were also cancelled as a precaution and might need to be halted again on Monday, Sydney Trains warned commuters.

“There may not be rail services to both the international and domestic airports tomorrow morning,” CEO Howard Collins said.

The workers injured in the incident – responsible for the erection of the crane – were treated at St George Hospital, with one of them suffering a suspected broken leg.

It is believed a mechanical or engineering fault caused the crane to collapse. Photo: Daniela Giorgiutti/ABC

Police said no one was inside the crane at the time.

Fire and Rescue Superintendent Josh Turner said the priority was to secure the site and make sure no one else was at risk.

“At this stage we are going to keep approximately 20 firefighters on site who are working with a USAR [Urban Search and Rescue] team and they have electronic movement devices on all areas around the building, the crane and the scaffolding to log what movement is happening,” he said.

High winds were also making the situation more dangerous, Superintendent Turner said on Sunday afternoon.

Exclusion zones will stay in place until further discussions with engineers, he said.

‘Could have seen many lives lost’

CFMEU NSW state secretary Brian Parker said early investigations determined it was a mechanical or engineering fault which caused the crane to collapse.

“We are very, very concerned about this particular issue,” he said.

“In this day and age, and all the expertise we have, it’s not good enough.

“We have seen cranes catch fire, fall out of the sky, but not cranes that collapse onto buildings that have residents.

“Our fears are not just for the workers that work to erect these cranes, but also the public.”

The CFMEU is calling for a halt on any further erections of cranes until investigations are complete.

“It could have been a major disaster here today and we could have seen many lives lost,” Mr Parker said.

Police have advised people to check www.livetraffic.com.au for updates on road closures.

– with AAP/ABC