A man has died after falling from the balcony of a unit complex in Sydney's north-west, with police treating the death as suspicious.

Emergency services were told shouting was coming from the balcony of a unit on Crane Road in Castle Hill at around 2.40am.

When paramedics arrived, they found a 44-year-old man with serious injuries in a garden outside the unit.

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They started treating him straight away, but he died at the scene.

Police have begun an investigation and set up a crime scene.

They are treating the death as suspicious.

A report will be prepared for the coroner, and anyone with information is urged to contact Crime Stoppers.

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