UPDATE: Police trawl CCTV footage for clues over Sydney underpass death

A woman whose body was found in a flooded underpass near her apartment block in Sydney's west had been anxiously pacing the lobby the previous night as if she was “waiting for someone.”

Police are investigating the circumstances of the woman’s death after emergency services were called to Bridge Road, Westmead at 7.30am yesterday.

Relatives reportedly found the body of the woman. She has been named by the Sydney Morning Herald as Amesha Rajapaske, 31.

Neighbours have described their shock at the woman’s death, describing the area where she was found as “dirty” and unpleasant.

Police are reviewing CCTV footage of the woman, which shows her walking to and from the back entrance of her Westmead unit four or five times yesterday evening.

Complex manager Tom Hailey said it looked as though the woman was waiting for someone in the footage.

He said the woman lived in a leased unit on the seventh floor of the apartment block.

The woman's body was reportedly found near a tunnel that runs under the adjacent railway line.

The tunnel became flooded very quickly after heavy rain, one resident told the Daily Telegraph.

Homicide detectives have been brought in to help local police determine if the woman's death was suspicious.

After some time the woman wedged her scarf in the door to keep it ajar and left, he said.

She was found dead the next morning.

It's believed the woman's husband and brother discovered the body.

They were led from the scene screaming: "Please, please, let me see her face," Macquarie Radio reported.

A resident at the Monarco Estate complex said no one ever went to the creek behind the block.

"No one goes there," she said.

"It's not a place where people walk through, it's not pleasant, it's dirty and the weather's been bad."

The death has shocked locals, especially a resident who was from the same level where the woman lived.

"I've never seen anything like this ... and I moved from America," he told AAP.

The neighbour had just moved in three weeks ago but was already considering finding a new home.