Help sought to ID dead Sydney woman

The circumstances surrounding an unidentified woman's fall from an apartment block in Sydney's north remain a mystery.

Police are appealing for help to identify the woman who fell from the Chatswood building some time before 8.20pm on Friday.

She is described as Asian in appearance with shoulder-length dark hair and is believed to be aged in her 20s, police said.

She was wearing white pyjamas and glasses when she fell.