07/02/2017 1:58 PM AEDT | Updated 07/02/2017 6:46 PM AEDT

Sydney Apartment Building Declared Safe After Fears It Would Collapse With 100 People Evacuated

Residents have been told they can return to their apartments.

A residential apartment block in Sydney's inner west has been declared safe enough for residents to return, after it was found to be on the verge of collapse on Tuesday.

An estimated 100 people were evacuated.

A NSW State Emergency Services (SES) spokesperson told the Huffington Post Australia structural engineers were called in on Tuesday afternoon to inspect the building before declaring it safe and the all-clear was given.

Earlier, a NSW SES spokesperson Stephanie Sullivan confirmed the building in Marrickville on Ewart St was at risk after severe storms dumped more than 48mm in an hour.

"There appears to be a water hole behind the apartment block that's threatening the foundations of the property," she told The Huffington Post Australia.

A short time later, Fire and Rescue NSW evacuated the building and it was unclear whether people would be able to return tonight.

Wolter Peeters / Fairfax Media
The apartment block backs onto a water hole where there's been dramatic erosion.

Heavy erosion can be seen at the waterhole, mere metres from the edge of the apartment block.

Wolter Peeters / Fairfax Media
Engineers inspect the building.

Ewart St resident Barry Rockliffe lives nextdoor and told The Huffington Post Australia the base of his building Selicia Gardens also flooded.

"We're one of three buildings that backs onto a weird, old waterhole but next door is much closer," he said.

Wolter Peeters / Fairfax Media
The waterhole behind the building.

"SES has been here pretty much all afternoon and they evacuated this afternoon but it's all quiet here now.

"It's a common site to see the basement flooded. There's something wrong with drainage in this part of Marrickville -- it floods every time we get about 25ml."

Sullivan told HuffPost Australia there had been 120 call outs across the state on Tuesday by 2pm as severe storms rolled across the city.

"The majority of these calls for help have been in the Sydney metro area and 13 have been flood rescues," Sullivan said.

"All the flood rescues have been right in the inner west area near Zetlands and Alexandria."

Marrickville recieved 48mm of rain in an hour on Tuesday but the Bureau of Meteorology said the immediate threat of severe thunderstorms had since passed in NSW.